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AN INTRODUCTION TO NATURE STUDY.

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MACMILLAN AND CO., Limited

LONDON . BOMBAY • CALCUTTA
MKLBOUKNIC

THE MACMILLAN COMPANY

NKW VOKK • BOSTON • CHICAGO
ATLANTA • SAN FRANCISCO

THE MACMILLAN CO. OF CANADA, Ltd.

TORONTO

AN INTRODUCTION

#T0

NATURE-STUDY

EkNEST STENHOUSE, B.Sc. (Lond.)

ASSOCIATE OF THE ROYAL COLLEGE OF SCIENCE, LONDON ; JOINT-AU THOR
WITH A. T. SIMMONS, B.SC. OF “ SCIE:NCE OF COM’#3N LIFE”

MACMILLAN AND CO., LIMITED
ST. J^ARTIN’S STREET, LONDON

1910

First Edition ](K)ri

Reprinted 1004 (twice), 1906, 1000, (with additions) 1908, 1910.

GLASGOW : PRINTED AT THE UNIVERSITY PRESS
BY ROBERT MACLKHOSE AND CO. LTD.

PREFACE.

One of the most encouraging of recent educational move-
ments is the increasing importance attached, both in this
coimiry and abroad, to what is called Nature-Study. It
is evident that the instruction coiilemplated differs as
widely, on the one hand, from the traditional object-lessons
*on polar bears and ironclads, as it differs from formal
Biology on the other. This difference is abundantly
shown, not only by the circulars and syllabmses issued by
our own Board of Education, but by the publications of the
leading educational authorities of Europe and America.
The aim of Nature-Study, as thus laid down, is not
primarily the acquisition of the facts, of natural history :
it is rather a training in methods of open-eyed, close, and
accurate observation, especially of familiar animals and
plants, which shall teach the student to see what he looks
at, and to think about what he sees.

It is in a spirit of entire agreement with these views
!hat this book has been written. No previous knowledge
of Biology on the part of the reader is assumed, and
technical terms have as far as possible been dispensed
with. In drawing up the course, I have had in mind
throughout the attitude of an intelligent youth of sixteen,
and the woik will be found to be well within the
powers of such a student. Teachers will, however,

Vi PREFACE

4 * — ^ * —

find no difficulty in adapting the exercises to the needs
of younger pupils. *

Care has been taken to select, as types for study, •animals
and plants which are at the ^me trifle representative and
easily obtainable,^ and I have been further guided in the
'selection |jiy the Board 6f Education Syllabuses of the
King’s Scholarship Examination and Section I. of the
Elementary Stage of General Biology, tjje subjects of which
are included in the volume. The book h^g, however,
a considerably wider scope than is indicated in theee
syllabuses, and will therefore, I hope, be found useful not
only in schools and training-colleges, and to examination
candidates, but also to members of field clubs aRd to
students of natural history generally. It has been neces
sary to arrange the chapters with some attempt at logical
sequence, but it is not supposed that this order will be<
adhered to in practice ; by the aid of the monthly nature-
calendar, together with numerous cross-references, it will
be found easy to take up the work at any .point.

The chapters are divided into sections. ea(^ of which
consists of two parts : First, precise instructions for
practical observations and experiments, designed to
exercise the reasoning faculties of the students ; and,
second, a descriptive portion, in which the meaning
and relation of the results obtained are discussed. At
the end of each chapter is a number of additional exercises,
either original or taken from past examination papers. Of
the latter class, questions to which dates are affixed have
been set by the Board of Education, while those marked
“ N.F.U.’’ are selected from National Froebel Union tests.

^ If any difficulty is found in procuring plant-specimens, they may be
obtained by post from the British Botanical Association, Ltd., Holgate,
York. The names of dealers prepared to supply varTous animal-speci-
mens are mentioned in the text.

PREFACE vii

In many cases, the exercises provide Subjects for further
observation and experiment, as well as for written descrip-
tion. ‘

Much trouble has* been taken in the selection of the
illustrations, many of which have been expressly drawn or
photographed f9r this book. Through the kin^pess of the
publishers I have been able to include illustrations from
Strasburger’s Text-£ook of Botany^ Parker and Haswell’s
Text-Book of Zoology^ The Cambridge Natural History^ and
other books ; and Mr. Ernest Evans has courteously con-
sented to the use of a number of figures from his Botany
for Begifiners. 'Fhe following illustrations have been
prepared from photographs supplied ^by Mr. J. C. Shen-
stone, F.L.S., Vice-President of the Essex Field Club :
Figs. 2>, 57, 65, 67 to 71, 74, 75 > B4, 85, 87,

89, 92, 94, 95, 102 to 110, 120, 136, 145, 149, 152
and 153; while Figs. 180, 196, 200, 201, 203, 205, and
211 are reproduced, by permission, from Pike’s Woodland^
Fields and Shore (Religious Tract Society).

Finally, I must acknowledge gratefully the continuous
help which, at every stage in the preparation of the book,
1 have received from Professor R. A. Gregory and Mr. A.
T. Simmons, B.Sc. — help as valuable as it was generous.

The issue of a new edition has provided the opportunity
of adding a section on School Journeys, originally contri-
•bffted by me as an article to The School Worlds and
reprinted here by kind permission of the Editors of that
journal. For the illustrative sketch-map (iMg. 237), and
for Figs. 19, 21 and 138, I am indebted to my friend
Mr. T. D. Tuton Hall.

E. STEN HOUSE.

CONTENTS.

PARTI. PLANT LIFE.

HAPTER

I. Seeds and their Early Stages of Growth,
fl. How a Green Plant Feeds,

III. The Forms AND Duties OF Leaves,

IV. • Buds. The History of a Twig, -

V. How Stems do their Work, - - - .

VI. Some Common Flowers, . - - • -

VII. Grasses,

VIII. Common Forest Trees,

IX. Fruits : How Seeds are Scattered, -

X. Ferns and Horsetails,

XI. Mosses, Mushrooms, and Moulds,

PART IL ANIMAL LIFE.

XII. The Rabbit : A Typical Mammal,

XIII. How a Rabbit Lives,

XIV. Some other Mammals, - - -

* •

XV. The Pigeon : A Typical Bird,

PAGE

125

140

165

183

199

211

222

246

265

CONTENTS

CHAPTER PACjK

XVI. The Development and Education of .the

Chick, , 282

XVII. Some Familiar Qrit;jsh Bi^:)S, - - - 301

^VIII. Frogs and Tadpoles, 332

XIX. T>he Habits and Life-Histories of Common

Insects, - - - - 349

XX. Some Crustaceans, Molluscs, and Worms, 372'

XXL Field-Work. The School Journey, - 388

Monthly Nature Calendar, - - 400

PART I.

n^LANT LIFE.

CHAPTER I.

SEEDS AND THEIR EARLY STAGES OF GROWTH.

! • THE STRUCTUEE OT SEEDS WITH TWO
COTYLEDONS.

I. Preparation of the seeds.— Obtain several se^ds of the broad
bean, pea, mustard, yellow lupine, vegetable marrow, and syca-
more ; soak them in cold or slightly warm water until they
are soft enough to be cut through easily with a sharp knife.
The time necessary will vaiy with different seeds according to
the size of the seeds, and with the temperature of the water.
The beans should be left in the water for a few days. When the
seeds are soft enough, examine one or two of each, and in the
meantime put about six of each (except the mustard) in damp
sawdust in a warm place. Put the mustard seeds on damp
flannel in a saucer.

• 2 . The outside of a broad bean. — Notice the flattened oval
shape, with an indentation at one place (Fig. i). What is the
colour of the skin {seed- coat) of the bean seed ? Is all the skin
of this colour ? A black scar extends along the edge from
the indentation for about | in. What is this scar? If beans in
the pod can be obtained, see that the scar is the p4ce of attach-
ment of the s%ed stalk. Make drawings to scale, showing side
and edge-views of the seed. Wipe the bean dry and then
N.S. A «

AN INTRODUCTION TO NATURE-STUDY

squeeze it gently. Notice that a drop of water come§ out at a
point at one end of the stalk scar. There is evidently a little
hole here. This little hole is called the micropyle. M^rk its
position by a dot on the drawing. * ^

3. The inside of a broad bean.-^With a sharp knife cut the
^seed-coat open, beginning at the side of the seed furthest from
the micropylg, and carefully remove the seed-coat. ' Notice that
near the micropyle the seed-coat forms a funnel-shaped depres-.
sion, and that the p(;|p 0 |f the funnel is at tlje micropyle. Does
anything fit into the 3 il*SPi€i|? A little cone may be seen to fill
the funnel ; this conical body is called the radicle. Make a
drawing of the seed after the removal of the seed-coat. Look
at the edge opposite the radicle and notice that a crack divides
the body of the seed into halves. Put the point of your knife
blade into the crack, and gently force the halves apart. They
come apart without tearing, showing that they are naturally
separate, although they fit so closely together.

These two swollen bodies are called the cotyledons. Separate
them and see, at the point where they join the radicle, a little
curved rod, evidently a continuation of the radicle, lying
between them. This rod is phantile. Take off one cotyle-
don, and make a drawing of the inner face of the othe^ cotyledon,
with the adhering- plumule and radicle (Fig. 2).

4. Starch present in the cotyledons of the bean.— Scrape the
inner surface of a cotyledon and then pour on it a drop of iodine
solution.^ Is there any change? Pour also a drop of iodine
solution on a piece of laundry-starch. Is a similar blue colour
formed ? What substance is probably present in the cotyledons
of the bean?

5. The pea.— Examine a pea in a similar manner. Make
drawings showing the stalk-scar^ the micropyle.^ and the plu^nnde «
and radicle with their manner of connection with the cotyledons.
Does the end of the radicle point towards the micropyle? How
many cotyledons has this seed? What shape and colour are
they ? Do they contain starch ?

' Made by dissolving one or two crystals of potassium iodide in about
half a pint of water, and then adding iodine in small qujTntities until the
solution is the colour of sherry.

THE STUDY OF SEEDS

6. Th€ seed of the yellow lupine.— Compare this with the bean
and the pea, and find out how many cotyledons it has, and
whefthbr they contain starch. Can you find the plumule ? It is
very small, but occujfles a position similar to that of the plumule
of the bean. Does the end of the radicle point to the micro-
pyJe?

7. The vegetable marrow seed. — Notice the peculiar shape
(somewhat like a pocket-flask) of th e^^iiid > and the thickened
margin which run# round it. Carefu^Hlt the seed-coat away
so as not to injure the part inside. H6# many cotyledons are
present ? What is their colour ? Do they contain starch ? Can
you see the plumule and radicle clearly? If not, do'^not decide
that they are absent, but leave the question to be settled later,
whan you watch a vegetable marrow seed “ come up.*'

8. The m\i8tard seed. — Notice how nfuch smaller this seed is
than the others. With a balance, find how many mustard seeds
are equal in weight to one bean seed. Observe the stickiness of
the seed-coat of the soaked seed, cand then remove it carefully
with needles, exposing two thin plates, each one folded on itself^
and one tucked inside the other, like two shec^ts of note-paper.
These are the cotyledons ; it seems that the smallness of the
seed may* be mainly due to the small size of the cotyledons.
What is their colour ? Remember these characters and try, when
you watch the young plants come up later, to find an explana-
tion of them.

9. The sycamore fruit. — The seed of the sycamore is enclosed
in a case which has a wing attached to it. The wing, the
case, and the enclosed seed together constitute the /rmf of the
sycamore. The fruits occur in pairs (Fig. 137). Notice that a
j:ord runs out to each fruit from the stalk on which the pair of
fruits is borne. Make a drawing of a pair of fruits, then
separate the fruits.

10. The sycamore seed. — Cut open a fruit. Can you see any-
thing between the seed and the fruit-case ? Would the hairy
covering of the seed tend to keep it warm duriug the winter?
Why ? Whf do you prefer to wear flannel in winter and linen
in summer ? Flannel is more fluffy than linen.

Remove the seed-coat carefully. Running down one side you

AN INTRODUCTION TO NATURE-STUDY

will see a little curved rod. This is the radicle. Gently raise it
with the point of your knife. Notice that the rest of the seed
seems to consist of a green part, wlych is curled up.. Uncoil
the curls carefully. You find that they ^e two green leaves,
fixed at the top of the radicle. These are the cotyledons. In
-ihe seed each cotyledon is first folded in two across the middle
and then coilvd up. Make a sketch showing the coils (Fig. 4).
Can you see the plumyuj^.'* It is just at the top of the radicle,
where the cotyledons ar<^ fixed on.

Plants are living things. — One of our foremost naturalists ^
tells us tHat when he goes out into the woods, or into one
of those fairy forests which we call fields, he finds himself
welcomed by a glad company of friends, everyone with
something interesting^ to tell. Such a feeling would be
quite impossible to one who did not vividly recognise
the fact that plants are alive ; for it is precisely this recogni-
tion or its absence which makes the observation of the
forms and habks of plants fascinating or the reverse. Let
the Nature-Student, then, at the outset of his work, keep the
idea of life inseparably bound up with his every thought
about plants. It may at first require a little effort, but
before long it will enable him to understand how the friend-
ship of the more silent half of animate nature may form one
of the great pleasures of life.

The study of seeds. — The manifestation of life is so
striking, and the changes in form and size take place so
rapidly, in the germination of seeds, that the study of plants
cannot better , be commenced than with this stage of their
growth. The method has also the logical virtue of begin-
ning at the beginning, or nearly so.

These early changes can be well observed by taking
various common seeds, soaking them in water until they are
soft, and then allowihg them to germinate in damp ‘sawdust,

^ Lord Avebury, The Pleasures of Life (Macmillan).

THE STUDY OF SEEDS

taking few out at intervals and noting their progress.
The growth of the seeds takes place more rapidly if they
are ‘kept in a warm room, but in any case some days
will probably elapse before much change is noticeable in
them.

.During the interval of waiting, some of theipseeds them-
selves should be carefully examined, and drawingrs of all the
parts should be nfdde. The drawing ought on no account
to be omitted. It compels the student’s attention to details
which would otherwise pass unnoticed ; and a careful sketch

Fig. I. — A Broad*Bean seed. A, side view; B, edge view: sf. sc.f
stalk-scar; ju, micropyle. (x§.)

is a much better record of an observation than any amount
of description alone could be. The drawing need not be
elaborate ; an outline pencil-sketch to scale will usually be
sufficient.

The seed of the broad bean. — The seed of the broad
bean (Fig. i) is large, having a diameter of perhaps an inch
and a half, and a thickness of half an inch. In shape it
oval, but at one region the edge is indented, and a black
scar (st sc) runs from the indentation along the edge for a
distance of about three-quarters of an inch. This scar is
the place of attachment of the stalk which formerly carried
the seed in the bean-fruit (pod). It may bg called the
Btalfe-scar,^ If a soaked bean is wiped dry sind' then gently
squeezed, a small drop of water escapes from the end of the
stalk-scar nearest the indentation. ' The hole out of which

AN INTRODUCTION TO NATURE-STUDY

the water comes is very small and difficult to see/ but its
position is thus made clear. This hole (/«) is called the
xnicropyle, — a word meaning the “ little gate.”

The bean seed is covered by a tough brown skin, the
4[e©d-coat (Fig, 2, i-.c.), a funnel-shaped depression in which
leads to the liiicropyle (m). The depression is occupied by. a
part of the seed which is shaped like a conical peg and called
the radicle (A^) ; the point of the radicle is directed toward
the micropyle. The great body of the seed is composed of

Fig. 2. — Broad-Bean seed, seen !rom the inside, after the removal of
half the seed-coat and one cotyledon. Ct;/ , the inner face of remaining
cotyledon ; C', area of attachment of other cotyledon ; m, micropyle ;
plumule ; k, radicle ; S.c,, seed-coat ; s^. sc., stalk-scar. (X i.)

two fleshy, cream-coloured lobes, easily wedged apart by
inserting a knife-blade between them ; these fleshy lobes
are the cotyledons ( O/.). Between them, and continuous with
the radicle, is a small yellow body, the plumule (//.). Th^^
relations of the radicle, plumule and cotyledons are best seen
by removing one cotyledon (Fig. 2).

A scraped cotyledon at once turns blue when a drop of
dilute iodine solution is poured on it, thus showing the
presence of starch. We shall see in Chapter II what use
the growing seedling makes of the starchy food which is
stored in its cotyledons.

THE STUDY OF SEEDS

The ^eed of the pea. — Except in size and shape the seed
of the; pea is very similar to the bean seed. Its form is
spherical, and the ^car ’ left by the stalk which formerly
attached it to the wall of*the pea-
pod (Fig. 3) is plainly to be seen.

Pointing towards the micropyle is
the peg-like radicle ; the plumule
lies between tffe hemispherical
cotyledons. As before, the coty-
ledons can be proved to contain
starch, by the blue colour which is
formed when a drop of iodine
solution is poured on the scraped
surface.

The «eed of the yellow lupine. —

The seed of the yellow lupine is
about as large as a pea, but it is
slightly flattened in shape. The
seed-coat • is prettily mottled ; p
when it is removed, the greater

part of the seed is found to consist of two cotyledons.
They are somewhat swollen, but the stored food is not
starch. The plumule and radicle occupy positions similar
to those of the bean and pea.

The vegetable marrow seed. — This seed has a rather
curious shape, and somewhat resembles a pocket-flask. It

flattened, and the border of the seed-coat is thickened
and of silky appearance, the rest of the “skin” having
some resemblance to kid. The two cotyledons, which com-
pose the greater part of the seed, are white and only slightly
fleshy. The plumule and radicle are at the pointed end of
the seed,, and are difficult to see.

The mustard seed — In comparing the mustard seed
with those already described, one is struck with the great

AN INTRODUCTION TO NATURE-STUDY

difference in size. An average broad-bean seed weighs about
600 times as much as the mustard seed. While the two
fleshy cotyledons make up the bulk of t^e seed of the bean,
pea, lupine and vegetable martow, the cotyledons of the
pnustard seed are thin and leaf-like. They are folded on
themselves, %one inside the other (as at g, Fig. 61), and
enclose the radicle. The characters of the cotyledons

5.C.

Fioi 4 .“Sycamore Fruit, cut through in the plane of the wing.

S.C., seed -coat (indicated by a thick, broken line); /.tv., fruit- wall;

Jk, layer of fine hairs ; R, radicle ; p/., plumule ; cot. i, cot. 2, cotyledons
(diagrammatically shaded), (xa.)

account very largely for the small size of the mustard seed.
It will be seen, when the growth of the young plants k
watched, that the difference is associated with the special
duties which the cotyledons perform in the various cases.

The sycamore seed. — What is generally called the seed of
rhe sycamore is really a fruit. The fruits are in pairs (Figs. 33
and 137), and each half consists of a flat wing aijd a rounded
case in which the seed itself is enclosed. The round seed-
cases of the two fruits are connected together. When they

THE*EARLY GROWTH OF SEEDS

come apart,* a scar marks the place where they were formerly
in contact, and a little cord runs out to each fruit from the
stalk on which the pair^f friiits is borne.

Between the sycamore seed &nd the wall of its case is a
layer of fine hair (/^, Fig. 4), which forms a warm nest for
the seed in winter. The seed is surrounded bf a thin,
brown seed-coat, and consists mainly of two cotyledons, but
^hese are very differeftt from any yet described. Each is
a green leaf, measuring, when unfolded, about an inch in
length. It is first folded across the middle of its length, and
then ' oiled up into a close coil with its fellow. The coils
are v< ry plainly to be seen when the seed coat is removed,
or when the whole seed is cut through, by a sharp knife, in
the plane of the wing. Running down one side of the seed
is a green rod, the radicle Fig. 4). The two cotyledons
(cot, I and cot. 2) spring from its upper end, and between
them is the tiny plumule (//.)

The sycamore seed bears more resemblance to the
mustard seed ^han to the others, but it is on a much larger
scale. In each of these two seeds the cotyledons are
plainly leaves, while in the others their nature is disguised
by the great accumulation of stored food in them.

2. THE EARLY STAGES OF GROWTH OF SEEDS
. WITH TWO COTYLEDONS.

If the seeds which were sown in damp sawdust and on
fiaiMjfil are kept warm they will soon be ready for study. You
should remember that at present your object is not so much to
rear the plants as to find out how they grow. As soon, there-
fore, as any sign of growth is to be seen when you take a seed
out, you should begin to examine them at regular intervals,
taking one or two out every day and leaving the rest tof^fcontinue
their developrftent Keep the sawdust damp, but not wet.

I. The pea and bean. — {a) General development , — Very soon
the seed-coat splits at the micropyle-end of the stalk-scar, and

AN INTRODUCTION TO NATURE-STUDY

the end of the radicle protrudes. Does the radicle grgw upwards
or downwards ? Observe that even if the seed was so planted
that the micropyle was at the tdp, th^ radicle turns over and
grows straight down. Turn over a seedling and see if you can
persuade the radicle to grow upwards. Open a seed when the
radicle is^about an inch long, and see what the plumule is doing*
It is stiJ] enclosed in the seed-coat, and lies between the
cotyledons, but is larger than at first. the growth proceeds
the cotyledons begin to separate near the top of the radicle,
you can get a glimpse of the plumule.

(d) The growth of the radicle. — Day by day the radicle
becomes longer. Is it all growing longer, or does the increase
in length take place more at one part than another 1 To
answer this question, take five or six inches of cottoft thread
and moisten the middle part with Indian ink. Lay the seed on
a flat ruler, so that the radicle lies over an inch divided into —
say — tenths. Hold the thread tight, and press the* inked pant
gently on the radicle, making about five marks at equal intervals
from the point upwards. The ink will dry almost immediately.
Then carefully replant the seed, taking care not to injure the
radicle. After a few days take it out again, lay i| once more on
the ruler, and measure the distance between the marks.

The radicle is evidently the yomvy root.

(c) The root- cap. — Hold up the radicle to the light, and
examine its tip with a lens. Try to see that the tip is covered
by a little cap, somewhat like a very small thimble. This is
called the root-cap.

{(f) The root-hairs. Hold a seed, with the radicle about an
inch long, against a dark surface. Is the surface of the radicle
smooth, or can you see any fluffiness on it? Is all the radicle
fluffy, or only a part ? Which part ? As you examine older and
older seedlings notice how much of the radicle is fluffy, and
where the fluffy part is. The fluffy appearance is caused by
fine, closely-set hairs, called root-hairs.

(e) The plumule.— soon after planting does the plumule
become free? Does it grow upwards or dowhwards? The
plumule is evidently the young stem.

As soon as the young stem is old enough mark it with Indian

THE iEARLY GROWTH OF SEEDS

ink as you fnarked the young root, and replant it to find if
there is any difference in the rates of growth of its different parts.

(/) The* fate of the cotyledons. — From time to time examine
the cotyledons and notic^that as* the seedling grows larger they
become more and more shrunken. Something is evidently
being taken from them, perhaps to feed the young plant. We
shall inquire into this by further experiment (Chapter ft.).

Do the cotyledons remain in their original position, or are
jdiey carried upwards ufth the growing stem or downwards with
me growing root }

2. The yellow lupine.— In the same way observe how this seed

grows. Do the cotyledons shift their position or change in
colour? Do they become leaflike? How do they differ from
later- formed leaves ? What becomes of them at last ? What
becomes of the seed-coat ? •

3. The mustard seed. — Notice that, soon after the radicle has
<jpme out o^ the seed-coat, a sort of hump forms at its upper end,
and at length the cotyledons are pulled out of the seed-coat and
turn up towards the light What is their colour ? Observe that
the two cotyledons are soon raised on the end of sT little stalk.
Like the cotyledons of the yellow lupine they are plainly leaves.
Notice their sliape. Are they of equal size? Why not? When
they are about three inches above the seed-coat gently separate
them and notice the little bud between them. Draw the seed-
ling. How large can you get a mustard seedling to grow on
damp flannel ? Plant a few mustard seeds on earth, and notice
the difference between the shape of tlie cotyledons or seed-
leaves and that of the leaves which appear later. What
becomes of the cotyledons ?

^The vegetable marrow seed. — Make similar observations
upon the vegetable marrow seeds, noticing particularly whether
the cotyledons remain in their original positions and shrink up
as the plant increases in size, or whether they are pulled out of
the seed-coat by the elongating stem, and become green and
leafy. How does the plant hold down its seed-coa$ whilst it
pulls out its cotyledons ?

5. The sycamore seed. — From what you have seen of the
cotyledons of the sycamore seed, will you expect them to behave

AN INTRODUCTION TO NATURE-STUDY

like those of the mustard seed, or like those of th^ ^ea and bean ?
Even in the seed they are green, and plainly leaves. How do
they escapse from the seed-coat.^ What is their shape? Do
they come out before or aft^ the radicle? Do they get any
larger as the stem grows ? How large can you get a sycamore
seedling to grow in damp sawdust ? As large as a seedling of
pea or I3fean ? Plant some sycamore seeds on earth and com.
pare the shape of the cotyledons with that of the next -formed
leaves. How soon do the “true” lliaves appear after thj
cotyledons have escaped from the seed ? Do any “ true ” leaves
grow on the plants in sawdust ? What becomes of the cotyledons
at last ?

The embryo. — The ^plumule, radicle, and cotyledons,
which have now b^en seen in the seed, form the embryo of the
plant. The adult plant will be wholly formed by the growth
and development of these parts, and we must ,now follow
carefully the changes which take place when the seed
germinates, and try to find out what becomes of each
part. It ffe better to put the seeds at first in damp saw-
dust rather than in earth, as the young rootj; can then be
more readily cleaned and observed. With small seeds the
early stages of growth are better seen if damp flannel is
used.

Germination. — Under the influence of moisture and
warmth the embryo* in the seed begins to swell and un-
fold its parts. The radicle makes its appearance first
(Fig. s), breaking through the seed-coat at the micropyle ;
it is the young root. The radicle always grows downviatfds,
that is, toward the centre of the earth. If the seed lies in
such a position that the micropyle is directed upwards, the
point of the radicle turns over and grows downwards as
soon as it escapes from the seed -coat. As the young root
becomes longer and thicker (Fig. 6) the se^d-coat opens
more and more, showing the cotyledons beneath, and these,
too, are gradually forced apart.

THE £ARLY GROWTH OF SEEDS

The cotyledons. — During the germination of various seeds,
a very marked difference in the behaviour of the cotyledons
is to be seen. In the^case*of the broad bean and pea the
cotyledons remain in their original positions, partially enclosed
by the split seed-coat. Presently a hump (Figs. 6 and ii)
forms at the upper end of the radicle, as if the pl<?nt were
making an effort to pull its plumule out of the seed. It
^on succeeds (Fig. i^s), and the plumule turns up to the

Fig. S-T-An early stage in
the germination of a Broad*
Bean seed. /?, radicle;
S.C., seed -coat. (X§.)

Fig. 6.— a slightly later sta
in the germination of a Broa
Bean seed. cot., cotyledon J
//, plumule; Ji, radicle; s.c., seed-
coat. (X^.)

light. It is the young stem. At its end is a little bud,
formed by a number of small, overlapping, green leaves
wh^ surround the growing point. Plenceforth the stem
grows upwards, that is in a direction precisely opposite to
that of the root’s growth. Both stem and root are attached
to the cotyledons, which gradually shrivel up as the stem
and root become larger and larger.

When, ho^yever, the seed of the mustard, or i(:rcamore,
germinates the cotyledons behave very differently (Figs.
7 and 8). Soon after the root has become well established

AN INTRODUCTION TO NATURE-STUDY

the cotyledUfes come quite out of the seed-coaf and unfold
themselves. Instead of remaining on or under the sur-
face of the ground ^hey are carried upwards
at the end of a stalk toward the light, and
for some time the little plant appears to
consist of root, stalk, and cotyledons only.
If, however, the cotyledons are gently
pressed apart, a tiny^bud is seen between
them. This evidently corresponds to tlTe
bud at the end of the stem of the bean or
pea.

In the case of the lupine (Fig. 9) or
vegetable marrow (Fig. 10) the cotyledons
Fig. 7.~M^ustard appear to Combine these . two conditions.

Seedling, showing

root-hairs and coty- They are swollen and contain stored food ;
ledons. (xj.) ^ ^

yet they come out of the seed-coat early,
become green, and open out to the light. They are
evidently •leaves, though their shape differs from that of
the later leaves.

• .

The germinating vegetable-marrow seed possesses a curious

Fro. 8. — Three stages in the growth of a Sycamore Seedling, cat., coty-
ledons ; /at., first pair of foliage leaves. (Slightly reduced.)

THE EARLY GROWTH OF SEEDS ‘5

contrivance for pulling its cotyledons out of tl^, seed-coat.

Fig. 9. — Three stages in the growth of the Yellow Lupine. On the
right the cotyledons are still enclosed in the mottled seed-coat. In the
middle plant the cotyledons are spreading out ; the first foliage leaves
haVe not ‘yet unfolded. On the left, the first two foliage leaves are
* unfolding, and the cotyledons have spread out flat. (Slightly reduced.)

This is a peg (/, Fig. to) which develops at tfie top of
the radicle, and holds down the lower
half of the se5d-coat whilst the other
half is forced upwards to allow the
cotyledons to be withdrawn.

After a little thought a possible
explanation of these differences in the
cotyledons suggests itself. It may be
that, in the case of the mustard and
sycamore, leaves are required as early
as pfJssible, while the bean and pea
have no immediate need for leaves
because their cotyledons contain so
much stored food. The cotyledons
of these plants shrivel up as the seed- {;e^coar^(f^J)'^^r^hdd

ling grows, anti this seems to indicate down to aiio^ the cotyie-
, ” . . dons to be withdrawn,

that during its early stages the plant (xi.) (After Bailey.)

l6 AN INTRODUCTION TO NATURE-STUDY

lives upon this food. In Chapter 11 . we shaJl make ex-
periments to see if this explanation is the true One. If so,
the lupine and ^egetable-marrgw seeds evidently tely partly
upon their stored food anc^ partl3f’upon setting the coty-
ledons to work as leaves, whilst the plant is still very
young.

The true leaves. — The cotyledons are really makeshift
leaves, which are already formed in the seeds. Even when
they expand and become green they do not live long, btf?

as soon as the next few leaves are
well established, shrivel up and wither.
The true or “ foliage ” leaves first
make their appearance as» a bud
which surrounds the growing point
of the stem. As this part of the stem
increases in length, the foliage *leav«s
become separated from each other
and spread out to the light and air.

The lengthening of the stem and
root. — Unless an expAiment to test
the truth of the matter is really made,
it might be supposed that the dif-
ferent parts of the stem and root of
the seedling grow in length at the same
rate. This can be tested by marking the stem and root with
lines of Indian ink at equal distances. In one experiment
with a pea seedling five lines were marked upon the young
root at regular intervals of one-tenth of an inch, beginning at
the tip (Fig. ii). The seedling was carefully replanted and
examined again a few days later. Between the tip and
the first mark there was then (Fig. 1 2) a distance of seven-
tenths of an inch ; that is, this part had grown to seven
times its former length. The second inteWal was four
times as long as before, the third was one and a half times

Fig. II. — A germinating
Pea; cot, cotyledon ; pi, plu-
mule ; R, radicle; r,h., root-
hairs ; .S’. «r., seed -coat. The
radicle has been marked with
Indian ink at intervals of

tH«;73early growth of seeds

as long, while the fourth and fifth intervals had not in-
creased in length at all. Such experi-
ments ’prove that the root grows in
length either at or jus? behind the tip.

When a young stem is treated in the
same way the lengthening is found to
take place more evenly.

Eootlets. — After af time the radicle
begins to put out branches called
rootlets. These come off the main root
in rows. In some cases rootlets make
their appearance whilst the radicle is
still vety short, as in the vegetable
marrow of Fig. 10, but in others the
radicle may be a few inches long be-
Ibre it produces rootlets.

The root cap. — The tip of the root,
and of each of its branches, is covered
by a little cap, shaped
somewhat like a
thimble (Fig. 13).

This protects the
tender growing point
from the friction of
particles of soil, and is continually re-
newed by growth from within as its
outer layers are worn away.

Boot hairs. — When a young root is
held against a dark background it ap-
pears fluffy. I'his appearance is caused
by a large number of very fine hairs
upon its surface. The ha|^ are not
found all over the root and its branches,
but only for a short distance a little way behind the tips
K.S. B

Fig. 12. ~ The Pea
seedling of Fig. ti, a
few days later.
cotyledons ; plu-

mule ; radicle ; S.c.^
seed-coat. (Xi.)

Fig. 13.— -The tip of a
root, showing the root-
cap. (Magnified.^

f8 AN INTRODUCTION TO NATUigS-STUDV

(Figs. 7 and ii). These root hairs are of vepy great im-
portance to the plant, as will be seen in Chapter 11.

3. THE STRUCTURE OFc URAfiTS OF MAIZE AND
WHEAT.

1. PrepUration of the seeds. — Soak grains of maize (Indian
corn) and wheat in water until they are soft. The grains of
maize will need soaking for several da>%. Plant about a dozen^
of each in damp sawdust, and in the meantime examine others.

2. The maize grain. — A grain of maize is really a fruit, as a
pea-pod is. A pea-pod contains several seeds ; a maize fruit
contains only one seed, which fills it. Notice the shape of the
grain — flattened, rounded along one edge, and bluntly pointed
at the opposite edge (Fig. 14). Notice a whitish patch on one
of the flattened sides; a ridge {E) down the middle of this marks
the position of the embryo. Cut through the grain*lengthwise,
so as to divide the embryo into two equal parts, and examine the
cut surface (Fig. 1 5). Identify :

{a) The <:jjibryo^ lying somewhat obliquely, and to one side.
The radicle {rad.) is directed towards the pointed end of the
grain, and the plumule (//.) towards the rounded end.

{b) The endosperm {end) : a mass of material outside the
embryo, and forming at least half of the grain.

{c) The scutellum {scm) : a plate lying between the endosperm
and the embryo.

{d) The coabs of the seed and fruit, surrounding the whole.

Draw, Add a drop of iodine solution to the cut surface of
the half-grain. The endosperm turns blue. What does this
indicate ?

3. Tlie wheat grain. — A grain of wheat is also a one-sd^ed
fruit. Notice the groove along one side, and — on the opposite
side near one end — the white patch marking the position of the
embryo. At the other end is a tuft of very fine hairs. Cut the
grain lengthwise, so as to divide the white patch into two equal
parts, and make out the embryo, endosperm, ^and scutellum
(Fig. 16). Draw. Test the endosperm wifh iodine solution.
Does it contain starch ?

grains of maize and wheat

Grains pTf maize and wheat. — A grain of maize or wheat
is reallj §i one-seeded finiit. In other words, the grain con-
sists not only of the s^ed W^th its seed-coat, but also of the
seed-case. In this respect it resembles the fruit of the
sycamore (p. 8). When, however, a grain of maize or
wheat is carefully examined, it is found to differ grmtly from
all the seeds hitherto mentioned. A maize grain is somewhat
flattened, and ratheP pointed along one edge (Fig. 14).

Fig. 14.— Maize grain, sho^
the position of the embryo
(X4.)

Fu;. 15.-— A longitudinal section of a
Maize grain, through the middle line of
the embryo, end^ endosperm ; pl^ plu-
mule ; rad, radicle ; rt, origin of a root ;
sem, scutellum. ( X 4.)

On one flat side, near the pointed end, may be seen a
whitish patch, and, along the middle line of this, a ridge
which marks the position of the e 7 nbryo,

A wlieat grain has a different shape. It is oval, with a
dggp groove running down one side. One end is clothed
with a tuft of very fine hairs ; near the other end, on the
side opposite to the groove, is a white patch beneath which
is the embryo.

These differences in shape are of small importance, for
the two grains are really of very similar structure^ as may be
seen when the^ are cut through lengthwise with a sharp
knife, in a direction which divides the embryo along its
midf^e line. It is then plain that each grain consists of two

AN introduction to nature^study

principal parts : the embryo and the endosperm^ (Figs. 1 5
and 16). The embryo lies to one side and in tjie lower
half of the seed. At its upper'end^^the young stem and at
its lower end the young root-^-each still enclosed in protect-
ing sheaths— are easily seen. The greater part of the seed
is quite eatside the embryo ; it is a mass of food called the
endosperm, which has been stored up for the use of the young
plant during its earliest stages of gerfhination. This food
mass at, once turns blue when a drop of
iodine solution is placed upon it, showing
that it contains a considerable amouht
of starch. It is the endosperm which is
^rnade into flour when corn is ground.

Lying between the embryo and endo-
sperm is a flat plate called tha scuteUum.
Covering embryo, scutellum, and endo-
sperm is the seed-coat proper, and out-
side that come the various layers of
the fruit case. ,

In the seeds previously examined, the
embryo — consisting of plumule, radicle,
a '’iongirndinai'^'^tiot cotyledons-was seen to fill the seed-
avSiS grab Completely. In some cases the
cotyledons were found to be more or less
swollen with stored food-material. - In the maize and wheat,
however, the embryo forms only a comparatively small pro-
portion of the seed, the bulk of which consists of stqj/^d
food called endosperm. This is a difference of- some im-
portance. Still more important, however, is the fact that
the two cotyledons, which were so conspicuous a feature of
the other seeds, cannot apparently be seen at all in these
seeds Are there then no cotyledons in the ^eeds of the
maize and wheat? If there are, how and* when 4 ^ they
appear, and what is their number ?

EARLY QROWTH OF MAIZE ANO WHEAT #1

4. THE ‘early stages OP GROWTH OP MAIZE

WHEAT.

I. The roots.— Watch for the* appearance of the roots. Is
there, as in the seedlings previously studied, one principal root,
or are there soon several, all apparently of equal or nefrly equal
importance? Do the roots grow straight down as before, or do
they spread horizontally^ ?

' 2. The stem and the cotyledon. — Notice that a rod, somewhat
thicker than a root, grows out near the origin of the roots, and
curves upwards towards the light. When this is about an inch
long on a maize seedling, slit it open carefully, and observe that
it consists of a pale outer sheath and a green core. The sheath
is the single cotyledon ; the green core is»the young stem en-
closed in a young Cut open the grain and notice
how the endosperm has shrivelled. As the seedlings become
Targer watch the young stem growing out at the end of its
sheathing cotyledon. What is the length of the cotyledon
when the stem first appears («) in the maize, {o) ir^the wheat?

3. The foliage leaves. — As soon as a foliage leaf unfolds make
a drawing of •its shape. Contrast it with the young foliage
leaves of the other seedlings. Hold up the leaves to the light
and compare the arrangement of their veins.

How maize and wheat seeds grow. — When the maize and
wheat fruits have been kept in damp sawdust for a few days,
the seeds — one in each fruit — begin to germinate. As a
rule the wheat plants have grown to a height of some inches
before the roots and stems of the maize plant have emerged
from the seeds.

The roots. — As might be expected, the first signs of life
make their appearance at the white scar which indicates thd
position of the embryo or young plant. Instead of one main
root growing^ out, several little roots make their i*ippearanoe
almost ^at the ^me time. They do not grow as directly
downwards as the radicle of a pea or bean (Fig. 6), but

AN INTRODUCTION TO NATUR£-STUDY

tend to spread in a horizontal direction (Fig. *17). It is
clear that in this way the roots are more independent of each
other than if they grew directly -downward side by side.

The cotyledon and the stem. — Growing out from the
seed close to the roots is another rod (Fig. 17, C), rather
thicker t 4 ian the roots, which at once curves upwards to the
light. It is pale green in colour. This is the cotyledon or

first leaf. •When it is carefully
slit open, it is found to be a
hollow sheath, enclosing a bright
green core. In the seedlings
which are left undisturbed, the
core at last breaks through the
tip of the cotyledon. It consists
of the young stem aijd its sur-
rounding foliage leaves. As the
growth of the plant continues,
these sheathing leaves unfold
themselves into the long narrow
blades characteristic of grass
leaves (Fig. 98). The bottom
ybf each leaf is tubular and forms
a sheath round the stem.

The endosperm. — The endo-
sperm, which at first made up

Fig. i7.-Young wheat seedling, more than half the seed, gradu-

C, cotyledon ; r, r, r, r, rcx)ts. (X 3.) i i t i

ally shrivels up as the Ijttle
plant continues its growth. The food material which it con-
tains is absorbed by the scutellum and is passed on to afford
the plant the necessary nourishment for those early stages
when it is too young to feed itself. By the time the first few
foliage leaves are well developed, all that remains of the grain
is an empty husk.

Oompaxisons and contrasts. — The examination of these

comparisons and contrasts

seeds and^ ’seedlings will enable the student to see that
differences, which at the first glance appear great, are often of
only minor importance^ while apparently small variations
may prove, on closer inspection, to be caused by deeply-
seated differences of structure and habits of life. He should
always set himself the questions, “ In what ways do fuch and
such objects resemble each other ; and in what ways do they
differ from each otlftr? Which of the differences and
resemblances are of most importance?” He should also
notice that a mere difference of size is often of very small
consequence.

Above all, the student should get into the habit of
asking the reaflons for the differences ^and resemblances
which he notices in his nature-study. To learn what these
reasons ar^ he must observe closely, think carefully, and
tiien make experiments to test the accuracy of his con-
clusions. Be sure you are right ; then look again ” ^
should be his motto. ' •

It is at oncp plain that the seedlings fall into two classes,
according to the number of cotyledons or seed-leaves which
they possess. The wheat and maize have only one such
seed-leaf, while the mustard, bean, pea, sycamore, and
vegetable marrow have two each. We shall see later on
that one-seed leaved plants differ from those with two seed-
leaves not only in the number of their cotyledons, but also
in the characters of their leaves and flowers and in their
m^od of growth. These differences are so constant and
so important that botanists have agreed to call all plants of
the first class (such as maize and wheat) Monocotyledons, and
plants of the second class Dicotyledons.

One of these differences is that the main roots of
dicotyledons^ are formed directly by the growA of their
radicles; while* in monocotyledons there is, after a short

^Prof. Comstock.

24 AN INTROPUCTION TO NATURE-STUDY

time, no such main root to be found, but several roots of
almost equal size spring from the base of the stem and
spread outwards in all directions (Fig. 17).

Both maize and wheat r seeds contain — outside the
embryo— a large store of food called endosperm (Figs. 15
and i6),^\yhich is not seen in any of the dicotyledonous seeds
described in this chapter. This is not a very important
difference, for, if we examined a vv^ry large number of
dicotyledon seeds, we should find that most of them
possessed endosperm. On the other hand, many mono-
cotyledonous seeds are destitute of endosperin. Only after
observing a very large number of facts is it safe to make
general statements.

Confining our attention to dicotyledons, we are impressed
by the great variation in size of the cotyledons. ^ Those of
the bean and pea are swollen with food material and form a
large proportion of the bulk of the seed. As a consequence,
the seedling lias enough food to enable it to grow into quite
a sturdy little plant before it needs any foliage leaves. The
cotyledons of the mustard and sycamore, however, are
thin, and they unfold almost immediately into green leaves,
and set to work to help to maintain the plant until the first
foliage leaves can be formed. The cotyledons of the
lupine (Fig. 9) and vegetable marrow (Fig. 10) serve a
double purpose. They not only contain a store of food
ready to hand, but they also set to work early to make new
food, until the new leaves are sufficiently advanced to take
up their duties It should be remembered that cotyledons
are makeshift leaves.

EXERCISES ON CHAPTER I.

I. Make a collection of the seeds of various tr^es;®try to find, in
each seed, the cotyledons, radicle, and plumule. Which of the seeds
contain stored starch ?

EXERCISES

2. Soak pine and larch seeds in water for several days and then sow
them, with a covering of half an inch of soil. Make notes of the
number, %hape, size, and behavjour of t*&e cotyledons. How large are
the seedlings at the end of#the first season ?

3. Make similar observations oh the growth of sycamore, ash, and
beech. Cover the seeds with an inch of soil.

4. Plant seeds of oak and chestnut two inches deep, andunake draw-
ings and notes of the stages of growth.

5. Investigate the str^icture and method of germination of a barley
seed, and find out whether barley is a dicotyledon or a monocotyledon.

6. Make experiments to discover the effects, upon the germination of
various seeds, of differences of temperature, moisture, and light, and
write full accounts of the results obtained.

7. Draw from memory a young seedling of maize, and notice its chief

peculiarities. ( 1 898)

8. Draw the seedling of the sycamore in twc»or more stages, and add

short notes. (1898)

9. Drav^ the root of any seedling that you have studied, giving its

name. Mark the exact position of the root-hairs. (1898)

10. Open the nut provided. Draw what is to be found in it in one
or two positions. Name the parts and give short explai^tions. (1901)

11. Explain, with drawings, how certain seedlings withdraw their

seed-leaves frogi the seed-coat. (*901)

12. Describe and explain as far as you can the principal changes to be

observed during the germination of a bean or pea. (1901)

13. Describe the germination of a bean, and compare it with that of

a grain of wheat. {1898)

14. Describe the structure ot a grain of wheat, and contrast it with

that of an acorn. (1896)

15. Plant seeds in wet, sticky soil (so that the air cannot easily get to
them), and compare their growth with that of similar seeds in a light,
open soil.

Two acorns are allowed to germinate, one in the neck of a bottle
full of water, and the other in an ordinary flower pot. What differences
will be noted in the two plants as they grow ? (Certificate, 1904)

CHAPTER IL

HOW A GREEN PLANT FEEDS.

5. THE FOOD WHICH A GREEN PLANT OBTAINS
FROM THE SOIL.

I. A plant cannot grow permanently in damp sawdust or clean
sand. — Notice that the seedlings which were grown 'in damp c
sawdust presently wither and die, while those which were grown
in soil flourish, and, with proper care, come to maturity. Obtain

some clean sand, and, to be
sure that there if* nothing in
it which water can dissolve,
wash the sand in several
changes of clean water. Ger-
minate some seeds in the sand,
keeping it damp. The result-
ing plants in this case also
wither and die. Evidently soil
contains some plant-food which
the plant cannot obtain fr^p
sawdust or clean sand. What
is this food ?

Fig. i8.— Porcelain crucible heated by „ ^ ^

Bunsen burner. 2. The amount Of Water and

mineral matter In plants. — Take
a healthy plant, say a bean plant, and weigh it. Then dry it
thoroughly in the oven and weigh it again, ^t mil be found
very much lighter ; the difference in weight represents the water
which has been driven off. Burn the dried plant. When the

PLAJ^r FOOD OBTAINED FROM SOIL 27

flame goes out notice the black charcoal which is obtained.
Continue the heating and observe th^t at last nothing is left but
a littM grey ash. This experiment can be performed over an
ordinary fire by using a‘R old shovel or a tile, but if you can use
a porcelain crucible (without lid) and a Bunsen burner (Fig. 18)
you will get better results. If a chemical balance is available,
weigh the ash and compare it with the weight of as!i obtained
from an ordinary bean seed, such as that which gave rise to
the plant you have used.

The ash from the plant is much greater than that got from
the seed. This extra ash must have been taken from the soil
during the plant’s growth.

3. A nutritive solution. — Make, or ask a dispensing chemist to
make,^he following solution :

•

Potassium nitrate (consists of potassium^ nitrogen^

^nd oxygeH)j i gram.

Sodium chloride (consists of sodimn and chlorine\ \ „

Calcium sulphate (consists of calcimn^ sulphur^

and i^xyjrept), • - i ..

Magnesium sulphate (consists of magnesium^

sulpfiur^ and oxygen\ i »

Calcium phosphate (consists of calcium^ phos-
phorus^ and oxygen\ i »

, Water, i litre.

(A few drops of a dilute solution of sulphate, or chloride, of
iron should be added.)

Water, with this solution, a plant growing in wet sand, and
when it is well grown, dry and burn it. As much ash is obtained
a^ from a plant of the same size grown in soil. Notice the
difference between such a plant and one which has had water
only supplied to it.

4. Water culture. — Fix two similar young plants in corks as
shown in Fig. 19, and put the corks into two bottles, the first
of which contains pure water and the second |he nutritive
solution, and lej the roots of the seedlings dip into the liquids.
Cover the outsides of the bottles with rolls of paper to keep out
the light. Notice that the plant living in the nutritive solution

AN INTRODUCTION TO NATURB^STODY

thrives, while the other presently withers. Dry an 5 ^ burn the
former, and observe that it yields more ash than does a seed
such as that from which it sprang. *

5. Plants obtain their mineral food flrJm the soil by their roots.

— As the roots are the only parts of the plant which are in
contact with* the nutritive solution, or which (under ordinary
condition^ are in the soil, the mineral matter must be taken in
by the roots. ^

6. The root-hairs. — Take up a seedling which has been

growing in damp sand, and observe the small particles of sand
adhering to the root-hairs (p. 17). The hairs of a plant’s root
and rootlets apply themselves very closely to particles of soil
(Fig. 20), and the mineral food (dissolved in water) passes into
the hairs and so gets into the root and thence to the other parts
of the plant. '

7. Roots as storehouses of food. — Examine, before the plants
flower, the roots of a turnip, a carrot, and a radish, and ,
notice how greatly they are swollen. You know that these roots
are valued as foods ; of what use do you think the stored food
is to the plants themselves ?

The food of a young seedling. — When such a seed as
that of a bean is germinated in damp sawdust or wet clean
sand, and kept in a warm and light place, it puts out
radicle, which grows downwards and becomes the main
root, and a stem which grows upwards and bears green
leaves. After a time the main root branches, giving off side
roots, which spread in all directions through the sawdust or
sand. The main root and the rootlets bear very fine fluffy
hairs for a short length, which is situated just behind their
points (Fig. 1 1 ), and these root hairs come into very close
contact with particles of damp sawdust or sand (Fig. 20),
the moisture passing into them and thus reaching the main
root, from which it is distributed to the various parts of the
plant. The stem likewise flourishes, growing in length and
thickness, and putting out new leaves.

PX;ANT FOOD OBTAINED FROM SOIL

All this time the young bean plant is living on the food
material^ stored up in its cotyledons (p. 6) ; and if the sand
or sawdust is kept mgist, Vith even pure water, this seed
food is at first quite sufficient When at last the seed food
is all used up, however, and all that remains of the cotyle-
dons is a shrivelled skin, the plant begins to cftoop and
wither from lack of food.

Plants obtain foo*d from the soil. — Contrast this with
the condition of a seedling which has been grown in soil.
It still flourishes, even when the seed food is used up, for it
is drawing up food from the soil — food which could not be
obtained from the damp sawdust or clean sand.

Thaf the plant really has taken up. some solid matter
from the soil can be proved by a few simple experiments.
A plant vjaich has been growing in soil for s6me time after
*its seed food is used up is dried and burnt, and the ashes
are weighed. The weight of ash or^ mineral matter thus
obtained is found to be considerably greater fSan that of
the ash obt^ned from an ungerminated seed, or from a
seedling grown in damp sawdust or sand which has only
been supplied with pure water.

The mineral food of plants.-— The composition of the
ash obtained from various plants has been carefully deter-
mined by chemists, and in this manner they have been able
to find out what substances must be present in soil in
order that the plant may obtain all the mineral food it
requires. A mixture of potassium nitrate (nitre), sodium
chloride (common salt), calcium sulphate (plaster of Paris),
magnesium sulphate (Epsom salts), calcium phosphate, and
chloride (or sulphate) of iron — dissolved in water in the
proportions specified on p. 27 — has been found to supply
the necessary elements of the mineral food in a fbrm which
the plant can r&dily use. That such a mixture is capable
of supporting the plant, while water alone is incapable of

AN INTRODUCTION TO NATURB^STUDY

doing so, may be seen by growing a plant — in tfie manner
shown in Fig. 19 — in this solution. If, in addition, the

t plant* is supplied with light and
frtfsh air, it will grow in a
perfectly healthy and normal
manner. If any of the con-
stituents (except the common
salt) are omitted, the plant will
suffer. On the other hand, a
plant which is growing in pure
water will presently die, from
the lack of the necessary mineral

The work of the roots. —

These experiments snow that
water — of which a large pro-
Fio. 19.— Plant growing in a portion of a plant consists —

nutritive solutltn o? salts. The , , . , ^ -

bottle should be covered with a roll and the mineral constituents of
of paper to keep out the liglu. (dissolvecj in the SOil-

water) are taken up from the soil by the roots. In ordinary
soil the rootlets spread out on all sides, dividing and sub-
dividing, seeking for this very weak solution of mineral
salts. Even when soil appears practically dry, a very thin
film of moisture covers
each little particle of ’
earth, and the root
hairs become closely
applied to these little
particles (Fig, 20), so 2o.-Tip of a root hair with adhering

^ VO /’ particles of soil. (X240.)

that the water passes

through their walls and gradually makes its way to the
main root, the stem, and the leaves. *

Roots sometimes perform other duties* in addition to
those of fixing the plant in the soil and providing it with

PLANT JFOOD OBTAINED FROM THE AIK

3 ^

water and mineral food. It is usual, for example, for
biennial ^plants — which produce flowers and seeds in their
second year, and thejj^^dife — to take in much more food
during their first season tharr they require at the time, and
to store up the surplus in readiness for the great effort of
the second year. These reserve materials are offhn storesj^
in the roots, which then become swollen and fleshy, like
those of the turnip, fadish, and carrot.

6. THE FOOD WHICH A GEEEN PLANT OBTAINS
FEOM THE AIE.

I. Pte-nts contain much carbon. — Char a stick, and notice the
black charcoal which is foi-med. Charcoal is an impure form of
carbon.

^ 2. Carbon dioxide gras is formed when wood bums.“Fastenva

shaving or a splinter of wood on a piece of wire, light it, and
lower it into a clean glass jar. When the w'ood has burned for
a few seconds take it out, and pour a little clear liifle- water into
the jar. The lime-water turns milky. Similarly, pour a little
lime-water into a jar in which nothing has been burning, and
notice that it remains clear. There is evidently a difference in
the nature of the air of the two jars. The difference is caused
by the burning of the wood, during which some of the carbon
unites with the oxygen of the air in the jar, forming an invisible
gas, called carbon dioxide. Carbon dioxide can always be
detected by the milkiness it causes in clear lime-water.

3. Carbon dioxide present in ordinary air. — Pour some clear
lime-water into a blue saucer and let it stand exposed to the air
for half an hour, then examine it. A white scum has formed on
the surface of the lime-water. Stir with a glass rod ; the
solution becomes milky. The scum and the milkiness are
produced by the union of the lime with carbon dioxide from the
air. Carbon (in the form of carbon dioxide) is therefore present
in the air. •

4. No carbon in the food solution. — Examine again the list of
elements (p. 27), which compose the mineral salts which have

AN INTRODUCTION TO NATURB-STUDY

been found to replace satisfactorily the food wbi(!h a plant
obtains from the soil. There is no carbon in it. * A plant
evidently does not depend on the soil for the carbonaceous
part of its food. From what o^her sdbrce can a plant obtain
its carbon ? Carbon has just been proved to be present in the
air. Doqg the plant obtain its carbon from the air ?
yf 5. Green leaves contain starch after exposure to sunlig^l^t. — Take
a green leaf from a plant which has been exposed to the sun-
light, boil the leaf in water for a minute Sr two to kill it. Then
put it in methylated spirit until the leaf-green is dissolved out.
When the leaf is bleached rinse it in water, then put it into a
dilute solution of iodine (p. 2) and notice that it becomes blue
or purplish brown. The formation of this colour proves the
presence of starch in the leaf. ,

6. Starch contains 'carhon. — Char a piece of laundry starch
and observe the charcoal formed.

Green leaves do not contain starch after being Jeft in the
dark for 24 hours. — Keep a leafy plant in the dark for 24 hours*
and then test a leaf as in the previous experiment. No starch
can be detected. Put the plant in the sunlight for an hour or
two and test another ieaft It contains starch. Plainly, starch
is only formed in leaves if they are exposed to 'light, and any
starch previously present disappears when the plant is kept in'"
the dark.

8. A green plant kept in air from which the carbon dioxide has
been removed will not form starch in its leaves. — Obtain a large
glass bottle, such as those used by confectioners, and fit it with
a cork or indiarubber stopper through which passes a glass tube
bent^ as in Fig. 21. Care should be taken to make all tlfe
joints tight, and it may be necessary to soak the cork in melted
paraffin to ensure this. Pack the bend of the tube loosely Avith
pieces of soda lime, and in the bottle place a small jar con-
taining lumps or a strong solution of caustic soda. When
the apparatus is ready, place in the bottle a small plant or a leafy
twig in water (fuchsia answers very well), which has been kept
in the dark for 24 hours. The caustic soda in the jar very

^ Cheap glass tubing can easily be made soft enough to bend by
heating it in an ordinary batswing gas burner.

PLANT FOOD OBTAINED FROM THE AIR

soon absoil^s all the carbon dioxide which is present, and the
soda lime*in the bend of the tube prevents any carbon dioxide
from g*etfing into the bottle from the outside air. Place the jar
in bright sunlight for a f€w houjs and then test a leaf for starch.
None can be detected. It is plain that one of the carbonaceous
food stuffs — starch — is not formed in the leaves of plants unless
the plant is grown (in the light) in air containing carbon
dioxide.

9. Seedlings are at 8 rst independent of light. — Germinate pea
or bean seeds in wet sand or sawdust in the dark. Notice that
for some time the seedlings grow almost as well as when in the
light. Soon, however, the stem becomes long, weak and
straggling, and the leaves are pale in colour, even if the plant is
supplier! with mineral food.

10. The formation of sugar in a genniriSiting pea-seed.— Take
up a pea-seedling when the stem is one or two inches long, and

, chew the partly shrunken cotyledons. Notice the slightly sweet
taste. Contrast this with the taste of an ungerminated seed.

A plant contains much carbon. — When a piece of wood
or other parli of a plant is strongly heated it first blackens or
chars, showing the presence of a large proportion of char-
coal or impure carbon. On continued heating, this carbon
‘‘burns away.'' In the process of burning it unites with
some of the oxygen of the air, and forms a colourless,
invisible gas known as carbon dioxide. Though this sub-
stance cannot be seen, its presence can be easily detected
by means of clear lime water, which, when exposed to the
gas, absorbs it and becomes milky owing to the formation
of a white precipitate of chalk. If, for example, a splinter
of wood is burnt in a glass jar, and a little clear lime water
is immediately afterwards poured into the jar and shaken
up, a milkiness at once proclaims the presence of carbon
dioxide.

The air contains carbon.— If lime water is poured into a
blue saucer and left exposed to the air for half an hour, a
*N.S C

AN INTRODUCTION TO NATURE-STUDY

white scum of chalk is seen to have formed on its surface,
showing that carbon dioxide is present in the atmosphere.
It is important that the student should realise this presence
of carbon — as invisible carbon dioxide gas — in the air.
Although the proportion is very small, amounting to only
3 parts of carbon dioxide in 10,000 parts of fresh country
air, it is of incalculable importance to plants, and indirectly
to ourselves and all other animals.

A green plant obtains its carbon from the air.— Since
the parts of a plant contain much carbon, and the food
wl;iich a plant obtains from the soil need not contain any
carbon ; while the air, on the other hand, does contain
carbon, it seems likely that a plant obtains its carbonaceous
food from the air. This surmise is confirmed by ex-
periments. One of the most easily recognisable,, of plant
products containing carbon is staxcli, for it yields a very'
characteristic blue, or purplish-brown, colour when treated
with iodine^' solution. By means of this test starch can
easily be proved to be present in the green leaves of a
plant which hhs been exposed to the air and sunlight. The
leaf is first killed by being boiled in water for a minute or
two, and then its green colouring matter is dissolved out by
immersion in alcohol (methylated spirit). The bleached
leaf is rinsed in water and then put in iodine solution, and
the blue or purplish-brown colour which is formed shows the
presence of starch. There is a marked difference when a
leaf, which has been kept in the dark for twenty-four hours,
is similarly tested. In this case no starch can be detected.

One compound of carbon — i.e, starch — may thus be
recognised easily ; and if we found that a leaf made no
starch when supplied only with air from which the carbon
dioxide had been removed, this fact would „ be strong
evidence in favour of the conclusion that' a green plant
obtains its carbon from the carbon dioxide of the air. To

GREEN PEANTS OBTAIN CARBON FROM AIR 35

test thisj^a large bottle is fitted, by means of a tightly fitting
cork Of stopper, with a tube containing lumps of foda
lime, a substance whicj^^agerly absorbs carbon dioxide from
air. A small jar of caustic soda is placed inside the
bottle (Fig. 2i). A green plant or a leafy twig, which has
been kept for twenty-four hours in the dark to f^e it from
starch, is then put in the bottle, and the whole exposed to
sunlight for a few ^ours. At
the end of this time it is
found, on testing the leaves,
that no starch has been formed.

By this, and other experiments,
botanists have proved that
£ree^ plants obtain all their
carbon from the carbon dioxide
of the air^ and that sunlight is
indispensable for the process.

We shall examine this question
more fully, when we study
leaves (Chapter III.).

The carbonaceous food of a
young seedling. — Just as a
bean or pea seedling is for a
time independent of an outside
supply of m.ineral food— its roots needing only to be supplied
with water — so there is enough carbonaceous food also*
stored up in the seed to satisfy for some time the needs
of the growing plant — the stored starch being, gradually
changed into sugar and absorbed. For this reason a young
seedling will live healthily in the dark. When, however, the
seed-food is exhausted, or nearly so, the plant draws upon
the store qf carbon, which is present as carbt^n dioxide in
the air, for a* renewal of the starch and allied substances
which are necessary to it. As it cannot make use of this

Fig. 21. — Experiment to prove that
leaves do not make starch unless the
air with which they are supplied con-
tains carbon dioxide. .V, tube contain-
ing lumps of soda lime ; jar
containing a solution of caustic soda.

AN INTRODUCTION TO NATURErSTUDY

atmospheric carbon in the dark, it must henceforth be
supplied with sunlight or it will not
thrive. Plants* l^pt in the dark after
their seed-food is exhausted are pale in
colour and unhealthy. Their stems grow
long and straggling (Fig. 22), but are
usually too weak to stand upright.

EXERCISES ON CHAPTER II.

1. Make experiments to discover the effects,

upon seedlings growing in a nutritive solution
(p. 27), of each of the following modifica'i.ions in
th^ composition of the solution : {a) omit the

sodium chloride ; {h) omit the potassium nitrate ;
(f) omit the compound of iron ; {d) omit the
magnesium sulphate ; (c ) substitute sodium nitrate
for potassium nitrate.

2, Explain how it is that a green plant cannot

carry on its nutrition in darkness. (ii^92)

Fig. 22.~Two mus- What part of its food does a green plant

ag^ obtain from the air ? In what form, and under

dark; A, i^rown in what conditions, is it taken in ? (1889)

ordinary daylight ^ i i r

4. Describe the method of water cultures, and

give the general results of a set of experiments. (189S)

5. Give experimental proof that green plants require to be fed with

combined nitrogen. (1897)

6. What aie the necessary condition^ for the formation of starch in a
plant ? Mention experiments which support yt)ur statements. (1896)

7. Explain the influence of light on a growing plant. Illustrate youi
aii'.wer by reference to the changes in a ripening and germinating bean.

(King’s vSchol. 1903)

8. How can it be proved experimentally that a green plant draws

some, but not tlie whole, of its nourishment from the air? (1904)

CHAPTER III.

THE FORMS AND DUTIES OF LEAVES.

7. THE FORMS OF LEAVES.

1. The shapes. — Make a collection of Sic leaves of a large
number of different plants, for example, elm, beech, lime, oak,
birch, ash, blackberry, pine, yew, horse chestnut, rose, holly,
woodsorrel, grass. Lay each in turn flat in your notebook and
trace the shape of the leaf blade by passing the jioint of your
pencil round the edge. Measure the length and greatest width ;
write down t|jesc dimensions. Is the greatest width at, above,
or below, the middle of the leaf blade ?

Most of the leaves are flattened green plates. Those of the
pine and yew are long and needle-shaped. Do you know any
other leaves like these ?

2. The veins.-- What enables the leaf to kecji stretched out?
Turn it over and notice the “veins” on the lower side. Do
they act like the ribs of an umbrella ? Fill in the positions of
the main veins in your drawings. Are the veins parallel to
each other in any of your leaves ? Write a list of as many
leaves as you can find which have parallel veins.

3. Skeleton leaves. -Put some leaves in a saucer with a little
soft water, and allow them to rot. Clean away the soft stuff
from time to time by ge 7 itly brushing the leaves with an old
tooth-brush. Notice the “skeleton” which remains. Skeleton
leaves may •be yiade much more quickly by soaking the leaves
for some time in a weak solution of bleaching powder. ' Wash
them well before drying.

38 AN INTRODUCTION TO NATUREvSTUDV

4. The coloxir.-— Is the green deeper on^he upper or the lower
surface of a leaf? Which surface usually receives more light ?

5. The apex. — In how many of yo^r leaves is the apex (a)
pointed, blunt, (c) rounded ? ,

6. The margiXL— ;Examine the edge or margin of each leaf.
In how m^any is it {a) quite plain, (d) hairy, (c) wavy, (ci) saw-
edged, (e) doubly saw-edged, (/) spiny? Do you find spines on
holly leaves which are so high on the tree as to be out of the
reach of cattle ? What is the use of the spines ?

7. Blackherry leaves. — Gather several leaves from a black-
berry bush. Notice that in addition to the “saw cuts,” the
margins of some are cut into slightly, while others are divided
quite to the midrib, the leaf being thus cut into two or more
leaflets. Select specimens which form a gradual series bf?tween
the “simple” leaf and the “compound” leaf (consisting of three
or five leaflets) and draw them.

8 . Tlie horse chestnut leaf. — Draw the compound leaf of the
horse chestnut, and draw an even curved line joining the points
of the leaflets. You can imagine that the compound leaf may
have been fo, med by a leaf of this shape being cut into until it
was divided into seven complete leaflets.

9. The rose leaf. — Draw an imaginary simple leaf such as
may have been the original form from which the compound
leaf of the rose was derived. Notice the difference in the
arrangement of the main veins of the leaves of the horse
chestnut and the rose. Does this account for the leaflets
coming off at the sides of the midrib in the rose leaf, and
springing from one point, like fingers from the palm of the
hand, in the case of the horse chestnut ?

10. Sycamore and ivy leaves. — If the large indentations in
these leaves were continued to the midrib, would the compound
leaves thus formed be of the type of the rose leaf or of that of
the horse chestnut leaf?

11. The leaf-stalk. — What attaches the leaf-blade to the Stem

or branch of the plant ? Can you see signs of the main veins
joining the top of the leaf-stalk ? Do you know any plant with
the blades of the leaves fixed directly on the stem, Le, without
any leaf-stalks ? !

,THE FORMS OF ^LEAVES

12. StipTiles. — Examine the rose leaf again and notice the two
leaf-like outgrowths at the bottom of the stalk. These are

stipules. Make a list^of as many leaves as you can find
which have stipules, many leaves -can you find with a

sheath at the bottom of the stalk ?

13. The leaf of the sweet pea. — Notice the large stipules of this
compound leaf (Fig. 28). What are the tendrils !• Do you
think they may be mainly the larger veins of the upper leaflets ?
Is the leaf of the typefof the rose or of the horse chestnut leaf?

14. Other compound leaves.— Compare and contrast ash, lupine,
woodsorrel, strawberry, and other compound leaves with those
of the rose and horse chestnut.

A leaf. — The leaves of different plants vary much in size
and shape, but in general a leaf is a thin, broad, and more
or less oval hlade of green colour, attached by a leaf stalk to
the stem or branch. In some cases, however, the leaf
^ stalk is absent and the blade is attached directly to the stem
or branch.

The veins. — The leaf is kept taut by a numbor of branch-
ing ribs, somewhat as the silk of an opened umbrella is
stretched tightly by the ribs. The ribs or “ veins ” of the
leaf run beneath the skin, but are generally nearer the lower
surface than the upper, and are easily seen when the leaf is
turned over. If a leaf is allowed to rot in a little soft water,
the skin and the soft green stuff of the interior decay and
leave these veins as a white “skeleton ” (Fig. 23). The pro-
cess may be assisted by gently brushing the leaf from time
to time. A skeleton leaf may be obtained still more
quickly by putting the leaf in a tveak solution of bleaching
powder until the skin and interior are soft enough to be
brushed away. Care should be taken to use a weak solu-
tion, or the veins also will be rotted. The skeleton should
be well washed in water before drying.

The arrangement of the veins in a leaf varies widely, but
it falls broadly into two classes, according as the main veins

AN INTRODUCTION TO NATURE*STUDY

run parallel or nearly parallel to each other (Fig. 24), or
form a less regular network (Fig. 23). The ven6,tion of a
leaf is curiously associated with .the number of cotyledons
possessed by the seedling ; for.nea^all dicotyledons (p. 23)
have net-veined leaves, while the leaves of monocotyledons
are almost invariably parallel- veined. Careful drawings of

Fig. 23. — Net-veined leaf of a Fk; 24. -- Parallel vena-

dicotyledon (White Thorn). (xj) tion of the leaf of a mono-

cotyledon (Solomon's Seal).

(Xl)

several typical leaves should be made, and the principal
veins indicated on them.

The shapes of leaves. — Although the blade of a leaf is
most commonly flattened, and roughly oval in outline, there
are several exceptions. The leaves of pine, spruce, larch,
and yew are needle-shaped ; those of grasses (Figs. 102-ifo)
are very long in proportion to their width ; while the leaves of
many moorland plants are rolled up into hollow cylinders.
There is some reason — could we find it — for every such
variation, and the significance of some of these shapes will
be referred to later (p. 47 V When the dimensions of leaves
are carefully measured, the proportion of the length to the

TI^E FORMS OF LEAVES

width will be found to vary much in the leaves of different
plants, but will be found to be pretty constant for the same
sort of plant. This holds^pod, too, for the position of the
greatest width (e.g, at, aSove, or below, the middle of the
blade)^ the form of the a/>ex of the blade (blunt, i)ointed,
spiny, or rounded), the nature of the margin (smooth and
‘‘entire,” hairy, saw-edged, doubly saw-edged, lobed, etc.),
and the extent and posii^ons of the larger indentatums. Thus,
while any particular elm leaf (Fig. 124) is probably slightly
different from every other elm leaf in the world, it resembles
every other elm leaf more than it does any leaf from any other
plant than an elm. No leaf of this shape ever grows on an
oak tree f)r a sycamore. Thus, in spite of minor variations
there is a wonderful conformity to type, and the student will
find that by.carefully examining the shape, venation, margin,
a^ex, etc., of all his leaves, and above all by dra 7 tn?ig them,
he will soon be able to recognise them at sight. It is by
doing this and noticing in each case the methcxis ^ folding
and arrangement of young leaves in the bud that it may be
possible in the future to explain some variations which are at
present not ihiderstood. It has already been seen that the
peculiar forms of the leaves known as cotyledons arc associated
to some extent with the shape and size of the seeds containing
them, and with the amount, if any, of the food stored in them.

Simple and compound leaves. — Blackberry leaves (Fig. 76)
well repay close examination. Some of the leaves on the
bush will be found to be simple — having one blade only on
the leaf stalk. Here and there, however, a leaf may be dis-
covered which is so deeply cut into along one side, that it is
almost completely divided into two leaflets ; and other leaves
will easily be found which consist of three or five leaflets,
much resembling the leaves of the rose (Fig. 25), a near
relative of the blackberry. Flere, then, we have a plant
which produces simple or compound leaves according

AN INTRODUCTION TO NATURE STUDY

to its needs. It seems as if the blackberry wefe still trying,

as an Experiment, a device
whif^ the rose tree has found
A * advantageous as to have

adopted for good. Some other
* plants, the ash, for example,

compound leaves broadly
similar Ko the rose leaf — the
leaflets springing in pairs from
1 sides of the midrib.

I ^ aHLl tN- compound leaf of the

s.'”" horse chestnut (idg. 26) is of a

I different type, for the seven

^ leaflets all arise from one point;

m and the leaves of, the lupine

si” (Fig. 9) are arranged on the

JR same plan. When the vena-

F,<:. ss.-Compound leaf of the is examined, the reason for

5 °stipuies’. ^ ’ this becomes {jlain. In these

cases the main veins all diverge
from the top of the leaf stalk ; whereas in the rose and ash
the midrib gives rise to side ribs in pairs. The leaflets are

naturally arranged so that one of
the larger veins shall support
each. The next question arising
is, What causes the differences
in the methods of branching of
the midrib? At present this is
a mystery. Compound leaves
consisting of three leaflets are
found in wood-sorrel, strawberry
(Fig. 50), clover, etc.

Intermediate leaves. — The

ivy (Fig.

27) and sycamore

Fig. 26. -'Compound leaf of the
Horse Chestnut. ( x i)

THE FORMS OF LEAVES

(Fig. 33) have leaves which seem intermediate between truly
simple an<i truly compound leaves. From the arrangement
of the veins it is seen tha^^tiiey approach the horse chestnut
type more than that of the rose. * On the other hand, if the
deep indentations of the oak leaf (Fig. 113) were carried to
the midrib, the simple leaf would be divided into Teaflets
arranged, somewhat like those of the rose or ash leaf, along
the sides of the midrib?

Fig. 27— Ivy. (x^) Fio. 28.- t ompound leaf of

Pea. Fli Hower-stalk ; Sp^
stipules ; 7 ’, tendrils. ( x i)

Stipules. — At the bases of many leaf stalks, close to the
stem, are leaf-like outgrowths called stipules. They, are
well seen in the rose (Fig. 25) and pea (Fig. 28). Some
leaves have a sheath at the bottom ©f the stalk, partially
enclosing the s.tem.

Tendrils. — The* pea also affords an interesting case
of leaflets being modified to do special work. Here the

AN INTRODUCTION TO NATIMIE-STUDV

upper leaflets seem to have remained undeveloped except
for their main veins, and these have acquired a Remarkable
power of twining round suitable^ objects and so supporting
the stem. Many other pla*nts have tendrils, but these are
not always modified leaflets.

8. HOW LEAVES ARE ARRANGED ON THE STEM.

1. Opposite leaves.’ -Examine a dcadnettle plant (Fig. 92).
Do the leaves come off the stem haphazaul ? How many come
off at each level Are both leaves on the same side of the stem,
or opposite each other? Are the two leaves at the next level
al)Ove just over these, or do the directions cross? Do the
leaves get as much light or more than they would i^each pair
were just over the pair next below ? How many other plants do
you know which have leaves arranged in this manner ? Examine
leafy twigs of sycamore, horse chestnut (Fig. 40), atid ash. J^re
the stalks of the lower leaves of these twigs of the same length
as those of the upper ones? Is it any advantage for the lower
leaves to*iiave longer leaf stalks ?

2. Box leaves. — What is the arrangemenj in the box?
Examine paUicularly the young leaves near the end ot the
twig. Are the lower ones twisted? Can you suggest a reason
for this twisting ? Can you find any twigs in which no twisting-
has taken place? Are these untwisted twigs so placed that
they are equally exposed to the light on all sides ?

3. Alternate leaves. — Examine the arrangement of the leaves

on a wallflower stem. They come off alternately^ each springing
from a rib on the stem. How many ribs are there ? Look at
the bottom of the stem, where the leaves have fallen off, and
notice that each has left a scar Mark one of the scars with
your pencil and then count how many scars you pass before
coming to another on the same rib. How many times do you
wind round the stem in doing this ? You pass five leaves and
wind spirally round the stem twice. This is always the case in
the wallflower. ^ •

Examine leafy twigs of oak and pear trees. Here, too, the
leaves are alternate^ and every sixth leaf is above the first, and a

ARRANGEMENT OF I.EAVES ON STEM

line joining all the leaf-bases or scars between the first «and sixth
leaves would wind spirally round the stem twice.

What •is'die arrangement ^Ahe elm and lime ?

4. Leaves wMcli form a Fosette.T--Examine plants of primrose
{Fig. 81) and daisy. The leaves in these cases spring from
close to the ground and form a rosette. Notice that tho^ottom
of the leaf blade is much narrower than the upper part. Is any
saving of material obtained by this arrangement?

5. The position of branches and buds. — Look in the upper
angle between a leaf and the stem in all your specimens. This
angle is called the axil of the leaf. Can you see a bud in the
axil of the leaf? Can you find that a bud or a side branch ever
arises in any other position ? (The former positions of fallen
leaves are* marked by scars.)

To the beginner in nature-study leaves seem in the
nTajority of cases to be arranged on the stem of a plant in a
haphazard and confusing manner, and it is only after very
careful observation that a definite order and reg'dlarity is

seen to be always maintained.

Nodes and intemodes.—The level at which a leaf springs
from the stem is called a node (Lat. 7 iodus^ a knot), and the
length between two consecutive nodes is called an internode
(Lat. inter, between).

Opposite leaves. — It is best to begin the study of leaf-
arrangement by examining some such plant as the deadnettle
(Fig. 92). The leaves come off in pairs : two at the same
level, set opposite to each other. The next pair above or
below springs from the stem in a direction at ri^ht angles to
the first — a device which allows the leaves to get a moni
equal share of light than if each pair were placed directly
over the next below.

A similar arrangement is adopted by various other plants,
including the horse chestnut (Fig. 40), sycamore (Fig. 34), box,
privet, etc., but in some instances it is disguised. Box twigs

AN INTRODUCTION TO NATIVE-STUDY

afford an interesting* example of this. Those twjgs which are
equally, or almost equally, illuminated on all sides, have their
leaves arranged in pairs at rigi^angles to each other like
those of the deadnettle. Some twigs, however, receive the
light fj'om one direction only, and in these cases the leaves
turn themselves until they face the light ; so that at a casual
glance the pairs of leaves seem to lie all in the same plane.
One only needs to examine the ena of the twig, where the
leaves are just unfolding, to see that the arrangement is really
in pairs alternately at right angles. In the case of the
privet the efforts of the leaves to face the light often cause
the stem itself to be twisted between the leaf-levels.

The alternate, or spiral, arrangement. — Perhaps the
commonest leaf-arrangement is one in which only one leaf is
given off at any particular node, the next leaf being a liule
further round the stem, and so on. As a result, an ink line
or a piece of thread joining the leaf-bases would wind
spirally round the stem. In the case of the waUflower, oak,
pear, and many others, such a line would wind spirally twice
round the stem before coming to a leaf vertically above the
first, and in so doing it would pass five leaves. This may be
shortly described as the f arrangement. A less common
one is |, where in winding spirally round the stem 3 times,
8 leaves would*be passed.

Efforts of leaves to obtain light. — It would be difficult
to imagine any order of insertion which would .secure a
more equal distribution of light to each leaf than the spiral
arrangement ; but here also cases of leaves twisting in order
to face the light are not uncommon. Lime leaves very
often turn for this reason, so as to lie in almost the Same
plane — adopting a device similar to that of the box and privet
described above. Further, the lime leaves arrange them-
selves at such angles that there is very little over]apping 4
Elm twigs also often exhibit similar instances of a

ARRANGEMENT OF LEAVES ON STEM ‘ '

mutual accommodation of leaves to each other’s light
supply.

The lower leaves on chestnut twig have longer

stalks than those nearer the end (Fig. 40). This enables the
leaves to stand well out to the light and escape the over-^
shadowing of those above.

The positions of branches. — A branch of the stem of a
flowering plant always arises as a bud in the upper angle
between a leaf and the stem. This position is called by
botanists the axil of the leaf, from the Latin word axilla^ the
arm-pit. Clearly, then, the arrangement of the branches is
primarily dependent upon that of the leaves, and we shall,
for example, never find “ opposite ” branches on a tree which
bears its leaves on the alternate ” system. It is easy to
notice, however, that not all the buds develop into
b?anches. In other words there are many buds which remain
dormant, and the final arrangement of the branches is often
somewhat irregular on this account. But wherever an ordi-
nary bud or a branch occurs, we may be perfectly sure that
there was once a leaf immediately below, even if the leaf-
scar can no longer be seen.

Economy of leaf surface. — All these things seem to indi-
cate that a good supply of light is of the greatest importance
to leaves, and this conclusion is supported by the fact that
leaves are usually either narrow or actually cut away in
places where the light cannot reach them. The leaves of
the daisy and of the primrose (Fig. 81), for example, all
spring from nearly the same point, and form a rosette.
Evidently there would be a certain amount of overlapping
at the leaf-bases, unless the blades there were very narrow,
as they are. Again, the greatly-indented leaves of the ivy
are often arrar\ged so that a point of one leaf fits over
an indentation of another — a beautiful example of plant
economy.

CNTUODUCTION TO NATm<E-STUDY

9. THE WORK OF LEAVES. * .

r. In sunligTht leaves make starch. — Expts. 5, 7, and 8 (Sec. 6)
have already proved (a) that leaves of a plant growing in ordinary
air and»exposed to the sunlight make starch ; (d) that in the dark
this starch somehow disappears ; (r) that in air destitute of
carbon dioxide leaves are unable to njake starch even in sun-
light.

2. The parts of a leaf which are not exposed to light do not
make starch. — Keep a plant, say of tropa^olum — or, if not con-
venient, a single leaf (Fig. 30 ‘ ^ ^Fe dark for 24 liours to free
the leaves from starch. Split a small cork and })in the halves
on opposite sides of a leaf, and then expose the jilaiKt to bright
sunlight for an hofir or two. (If a single leaf is used let the end
of the stalk dip into water.) Take off the cork, kill the leaf with
boiling water, dissolve out the green colouring matter w^th
methylated spirit, rinse, and test with iodine solution. The part
from which the light was excluded leinains bleached, and there-
fore confliins no starch ; while the rest of the leaf becomes blue
or purplish brown owing to the presence of starch

3. Parts of a leaf whicti are not green do not form starch in
sunlight — Take a variegated leaf from a plant the varie-
gated geranium or maple) which has been in bright sunlight for
some hours. Apply the usual test for starch. The parts which
were originally green contain starch ; the originally white parts
remain bleached.

4. Leaves supplied with cartoon dioxide, and exposed to sunlight,
give off oxygen gas. — (ti) Take a bunch of fresh watercress or
any green water weed and put it in a beaker or glass jar. Cover
the plant with an inverted funnel which is shorter than the
beaker. Now fill the beaker with ordinary tap water or river
water {not distilled water), so that the end of the neck of the
funnel is covered. Completely fill a narrow test tube with
water, close it with the thumb, and invert it over the neck of the
funnel. If this has been done carefully the test tube will still be full
of water. Expose the arrangement (Fig. 29) to bright sunlight,
and notice the bubbles of gas which are given off from the plant

tl^E WORK OF LEAVE!

and collect al? the top of the tube. When a few inches of gas
have collected, raise the test tube, close it with the thumb whilst
still under ’water, and hold

it mouth upwards. In thM‘
meantime, light a splinter of
wood with the other hand.
When it is well burning,
blow out the light, remove
the thumb from the fest
tube, and plunge the glow-
ing splinter into the gas.
It bursts into flame again,
showing that the gas is
oxygen. *

(b) Repeat the experiment,
(i) placing the apparatus in
the dark, (ii) without using
any plant. No gas collects
in the test tube.

Fig. 29. — Experiment to prove that green-
leaves supplied with carbon dioxide, and
exposed to sunlight, give off oxygen gas.

(c) To show that the water used contains carbon dioxide im
solution, completely fill a gallon can or a large flask with similar
water, and attach a cork and a delivery
tube which has also been filled with*
water — dipping the end of the tube
into a little clear lime water (Fig. 30).
Put the same quantity of lime water
into another vessel for comparison, and
then heat the can. Oas is given off, and
as it bubbles through the lime water
the liquid is g^radually turned milky.

5. Leaves wither in sunlight unless
supplied with water. — {a) Cut off a leafy
twig and leave it exposed to sunlight
for an hour or two ; notice the change
in the appearance of the leaves.

{b) Put a simjlar twig in the dark for the same length of time;
again notice the leaves. Is the difference due to a difference in^
light or to one of heat ?

N.s. D

Fig. jo. — Experiment to
prove that tap- water, or river-
water, contains di.ssolved car-
bon dioxide.

so ''*AN INTRODUCTION TO NATyRE-STUDY

{c) To test this, keep, if possible, a similar twig* in the dark in
a warm place. Do the leaves wither as much as hi {a) ?

(<y) Smear with vaseline the under surface of some bf .the leaves
of such a twig and again expos?*t^-sunligdit. Do the smcaied
leaves remain fresh longmr than the others ?

(c) Cut off the end of a twig with a sharp knife whilst it is
under water, and leave it exposed to sunlight, dipping in water.
The leaves remain fresh. How do you explain these differ-
ences ?

V^6. In sunlight, leaves give off water. — Take a piece of card-
board about 4 in. square and make a small hole in the middle.
Pass the end of a leafy twig through the hole and make up with
wax any chinks between the twig and the card. Put the card
on a tumbler containing water, so that the end of the twig dips
under water ; and invert on the card — co\ ering the leafy end
of the twig — a second tumbler which is clean and dry. Put
the apparatus in the sunshine and notice the mistiness (or even
visible drops of water) forming on the inside of the upper
tumbler. Where does this moisture come from ?

7. The skin of a leaf is perforated by little pores. — Dip a fresh
laurel leaf into boiling water in a beaker or tumbler. Can you
see bubbles of air escaping from the leaf? Ate they to be seen
on both surfaces of the leaf, or only on one ? Which ?

Examine both surfaces of box leaves with a strong lens, and
try to sec the little dots (pores) on the lower surface.

The student who has performed the experiments described
in this section, and who has thought about the results
obtained, cannot but have gained some insight into the main
duties of leaves. The meaning of these results must now
be discussed.

The formation of starch in leaves.- When the green
leaves of a plant are exposed to sunlight in ordinary air
— that is in air containing a certain proportion of carbon
dioxide — the leaf forms starch in its interior, and the starch
can be detected by applying the iodine tes,st (p. 34). When
part of a leaf is protected from the light, as by pinning the

TME WORK OF LEAVES

halves of a^split cork on opposite sides of it (Fig. 31), no
starch is farmed in the shaded parts, but only in the regions
which are exposed to the Further, if a variegated leaf

is treated in the same way, starch can be detected only in
those parts of the leaf which were originally green ; the
parts which were white are free from starch. It is pi *n that
it is the green colouring matter which puts the energy of the
sunlight at the disposal of the leaf and enables it to manu-
facture starch.

Fig. 31, — A, Tropaeolum leaf, on which have been pinned the halves
of a split cork (^). ( x y)

B, the same leaf tested for starch with iodine solution, after exposure
to suiiHsht for an hour. 'I’he part shielded from the light remains
bleached ; the re^t of the leaf has turned blue.

At least three conditions are therefore necessary for the
formation of starch in leaves: (i) the green colouring
matter; (2) sunlight; (3) carbon dioxide.

Oxygen is liberated when leaves form starch. — Carbon
Aioxide, gas, which has been seen to be indispensable for
the manufacture of starch in leaves, consists of carbon, or
charcoal, chemically united with the gas oxygen. The green-
stuff of the interior of the leaf makes the starch by causing
this carbon to combine with water which has come up
from the roots, but it returns to the air the unnecessary
oxygen. Wat^ir plants, the leaves of which are not directly
exposed to the air, use carbon dioxide which the water has
dissolved from the air. They also give off the surplus

AN INTRODUCTION TO NATURE-STUDY

oxygen, after fixing the carbon. T^s is the explanation of
the bubbles of gas which, in sunlight, are often ^een rising
from the plants in an aquariuL such an arrangement

as is described in Expt. 9 , 4, This evolved gas can be collected,
and proved to be oxygen.

The use of water to the leaves. — It is common know-
ledge that if a twig is allowed to become dry its leaves hang
limply and wither; but if the twig is allowed to dip into
water the leaves will keep fresh and
crisp for a considerable time. This
necessity for supplying the ‘twig .with
water seems to indicate that leaves
give off water, and that this is so may
be proved by a few simple experi-
ments. Two tumblers may be arranged
as in Fig. 32 : separated by a card
through which passes the end of a
leafy twig. The end of^ the twig dips
into water in the lowg* tumbler. In
order to prevent water vapour from
passing from the lower tumbler to the
upper, the chinks between the twig
and the card are sealed with paraffin wax.

When this arrangement is placed in the sunlight, a dew
soon collects on the inside of the inverted upper tumbler.
This water must have been given off in the form of pour
from the leaves. That the loss of water from leaves is due
rather to the light than to the heat of the sunshine may be
shown by keeping leafy twigs in the dark. The leaves keep
fresh much longer than when placed in the light, even if
they are kept in as warm a place.

The pores of the leaf-surface. — An ordinary leaf remains
fresh much longer if its lower surface is smeared with vase-
line. The explanation of this lies in the fact that the water-

Fig. 32.— Experiment
to prove that green leaves,
closed to sunlight, give
on water.

TME WORK OF LEAVES

proof skin of a leaf is*, perforated by a multitude of little
pores, especially on the lower surface. In most leaves,
indeed, the pores are coi-^r'-^ to the lower surface. Smear-
ing the surface with vaseline blotks up these pores and thus
prevents the escape of water vapour from the interior of the
leaf •

These little mouths ^known as stomataY in the light
a nd close m cti e - d ark i -^^uring the daytime, theretore, the
aiF (containing its small proportion of carbon dioxide) has
free access to the interior of the leaf through the stomata,
andj^on tfie other hand, any water which the leaf does not
require can escape in the form of vapour. A leaf requires
water not only because all its mineral food^(p. 29) is brought
to it dissolved in water, but also because water as well as
carbon dioxide is required for the manufacture of the starch
and other plant-foods.

How plant-food is distributed. — The water which comes
up from the roots is distributed to the various parts of the
leaf through veins. These are therefore not only
supports, which stretch out the soft leaf-stuff to the light
and air, but they also form a very complete network of
irrigating channels or water pipes. Further, the starch and
other foods which a leaf makes are drained off into the stem
through other minute channels which are bound up with
the water pipes. The starch, for example, is changed into a
kind of sugar which dissolves in water and drains away.
From the stem, the food solutions are distributed to all the
parts where growth is taking place.

^ Greek, stoma^ a mouth.

AN INTRODUCTION TO NATURE-STUDY

EXERCISES CHAPTER III. "

1. Make drawings of as man$^ cases as possible of economy of leat
surface.

2. G“pw various plants, Tropreolum, Geranium, Fuchsia, Mustard,
etc., in the window, and notice the effect which the direction of the
light has upon the positions of the leaves. ^

3. Smear with vaseline the lower surfaces of various growing leaves,
and on the following day test the leaves for starch, comparing each with
an unsmeared leaf from the same plant.

4. How is the transpiration of water from a green leaf* effected and

controlled? Discuss the uses of transpiration. (1897)

5. Put the same quantity of water into each of two similar test-tubes,
and let the end of a' leafy twig dip into one. Weigh the tubes, place
them together in the sun for an hour, weigh again, and estimate roughly
the weight of water lost by one square inch of leaf surface per hour.
Compare various plants in this respect. Repeat the experiments, {a) in
a moderate light, {/)) in the dark.

6. Make a list of plants in which the leaves are so arranged as
{a) to conduct rain-water towards the base of the main stem, {d) to
cause rain-water to fall to the ground from the ouGide of the foliage.
Try to discover whethei the difference has any relation to the arrange-
ment of the roots.

7. Under what conditions can plants use carbon dioxide as a source

of food? Mention experimental and other proofs of the principal state-
ments made. (1905)

8. What part of its food docs a green plant obtain from the air? In
what form and under what conditions is it taken in ?

(King’s Scholarship, 1905)

CHAPTER IV.

BUDS. THE HISTORY OF A TWIG.

10. .THE STRUCTURE AND USES OF BUDS.

1. A typical bud. — Split a cabbage, or a lettuce “heart,” down
the middle, and observe how the leaves are arranged round the
oonical end of the stalk. The leaves which arc fixed lowest
on the stalk are the largest, and they cover the outside of the
bud. The leaves are smaller and smaller as they are fixed
ncaier and nearer the end of the stalk, until round th? tip they
are almost too sjnal) to be recognised as leaves. A hud is the
tip or “growing point” of a stem or branch, together wEh the
young leaves which crowd round it. Draw the section.

2. A sycamore twig. — Look in the axils (p. 47) of the leaves
of a sycamore twig in summer or autumn, and notice the buds.
Can you see any buds on the lower parts of the twig — which
bore leaves twelve months or longer ago? Did these also arise
in the axils of leaves ? Plow can you be sure they did ? Tie a
piece of string, or tape, round this twig and look at it often,
making a note of every change which you see in it.

3. The fall of the leaf. — On what date did you first notice that
the leaves of the sycamore were falling? Did the first leaves
fall from the twigs at, or near, the ends of the branches, or
lower down near the trunk ? Examine the scar left by the first
leaf which falls from your twig. What is its shape,? What is
the meaning of the dark dots on the scar ? Gently take off the
leaf nearest to the scar. Does it come off easily ? Are there
any dark dots on this scar ? Can you see anything on the end

AN INTRODUCTION TO NATORE-STUDY

of the leaf stalk corresponding to the dots ? Do you think the
•dots are the ends of the food pipes referred to on p. 53 ?

Make a drawing of a fallen^eaf and write dowd on the
drawing at the proper place, the cofdur of that part of the leaf,
•or better still, colour the drawing with water-colour paints.
Collect good specimens of the autumn leaves of as many other
trees as possible, and make coloured drawings of them.

On what date did you first notice ^that all the leaves were
shed ? Make similar notes for other trees.

4. The Btructiire of a sycamore bud. — In winter take off a
sycamore twig which has a big bud at the end, and examine it.
The bud is clothed with overlapping scales of a pale green
colour. Make a drawing of the bud, double the size, and then
take off the scales one by one and count them. Leok with a
lens at the upper end of one of the largest scales. Can you see
any trace of a rudimentary leaf blade ? When the last scale is
removed there remains on the end of the twig a tiny tuft pf
delicate green leaves surrounded by a little down. Count them,
and notice how each is folded up fan-wise. In some buds you
may find*‘a bunch of green flowers in the middle. These buds
are larger than those containing leaves only.

Cut a bud across with a sharp knife, and examine the cut
surface with a lens to^see more clearly how the scales and young
foliage leaves are arranged. Draw what you see.

5. How the bud bursts. — In spring watch your twig very
carefully to be sure you do not miss any stage of the opening of
the buds. Make drawings every day or two of the end bud,
when it has begun to unfold. Notice how the scales fall off—
those on the outside first— and how the foliage leaves push
open the upper scales and come out. Watch the way in which
each leaf opens its folds and spreads itself out flat.

The buds may be made to open earlier by cutting off a twig
about two or three feet long and keeping it in water in a warm
room. ^

6. Starch is stored up in the twigs. — Cut off a twig and pour a
drop of iodine solution on the cut end. What ’does the blue
colour indicate ?

7. The growth of the bud. — Watch your bud growing, and

STRUCTURE AND USES BUDS

notice that the tip of the twig— which was surrounded by the
young leaves— elongates so that each paii\ of leaves is soon
separated* from the next pair^j^ Notice the r//t£'s of scars which
the scales left when they fell off. ^

8. A year’s growth. — Look down the twig until you find the
rings or scars which wei*c left /a,s/ spring, when the ^ales fell
off the expanding terminal bud. A year ago the end of the twig
was at this point, so that the length between one such set of
rings and the next marks a year’s growth.

9. Side branches. — The buds on the length formed last
summer but one may have grown out into side twigs. Try to
find the leaf scars below each of these side twigs.

JO. A horse chestnut twig and its buds.— Examine in the same
way a horse chestnut twig and trace its history. The buds are
larger than those of the sycamore, and eacfli is covered with a
shining, sticky layer of resin. What do you think is the use of
Jhe resin } Put a bud in water, and when you take it out notice
how the water runs off and leaves the bud dry.

Pull one of the terminal buds to pieces. I'he scales will come
apart more easily if the bud is soaked for sopie time^n methyl-’
ated spirit, to dissolve out the resin. Notice the thick layer of
down inside the scales. What do you think is its use ? Scrape
the down gently, and carefully clean it away from the little
foliage leaves in the middle. .Sec how the leaflets of each leaf
are folded. In some terminal buds you may also find a little
pink flower-spray.

Tie a piece of string round a growing twig, so that you can
recognise it, and watch all the stages of the expansion of the
terminal bud, the unfolding of the leaves, and the elongation of
the tip (Figs. 37, 39 and 40). Cut off other twigs two or three
feet long, in February or early March, and keep them in water in
a warm room.

II. Other buds. — Examine the buds of the beech, lilac, violet,
dock, fern, etc., and make drawings showing (i) how the
leaves are arranged with regard to each other, and (2) how
each leaf is .folded or rolled. As a rule these points can
be ^easily made Sut by examining with a lens the cut surface
of a bud which has been cut across with a sharp knife ; but

AN INTRODUCTION TO NATURE-STUDY

the buds should also be examined at frequent intervals when
they are unfolding.

A typical bud. — An excellent idea of the structure of a
typical bud can be obtained by splitting down the middle an
ordinary cabbage, or a lettuce “ heart,” and examining the
manner in which the leaves crowd round and cover the con-
ical end of the stalk. Around the tip (fr ‘^growing point” the
leaves are extremely small and tender. They are overlapped

by slightly larger leaves,
which spring from the
stalk a little lower down.
These in their 1;urn are
covered by still larger
leaves, inserted at a yet
lower level, and so on— ^
the largest and oldest
leaves folding over the
smaller and more re-
cently formed. The
growing point of a stem,
or of a branch of a
sU^m, surrounded by a
cluster of immature
leaves, is called a bud.

The history of a sycamore twig. — The student who would
know the meaning of the various marks and scars on the
surface of a twig, should select one and follow carefully for
a year the fate of the buds which it bears. It is convenient
to begin by studying a twig on a sycamore tree. It may be
marked for ease of recognition by tying a piece of tape on
it. If several students are working, each should write his
name or number on a luggage-label and* fix this to his
twig.

Fig. 33. — Sycamore leaves .md fruits. (From
a photograph by Mr. A. Flatters.) (X jV.)

STRUCTURE AND USES OF BUDS

The positions of the buds. — In summer the younger twigs
of the ^oamore tree are covered with large five-pointed leaves
(Fig. 33). The leaves •cdifie off in pairs, each pair being
at right angles to the pair next above or below. Every leaf
is engaged throughout the day in building up — by jjieans of
the green stuff in its interior — starch and other foods (p. 50),
and in giving off excels water, in the form of invisible vapour,
through its stomata (p. 53). In the axil (p. 47) of each
leaf is a little bud, called from its position an axillary
bud (Fig. 4T, B), and at the very tip of the twig is a larger
terminal bud.

Autpjnn colours and the fall of the leaf — As the summer
wanes, the soil becomes colder, and th»^ chilled roots lose
much of their power of absorbing moisture. It is plain that
^if the leaves continued giving off water when no fresh
supplies were forthcoming the tree would suffer. How is the
danger to be met? Starch and other foods have already
been stored up in quantity sufficient to supply the needs of
the winter and the early spring. The leaves have finished
their work, and one by one they fall off. But this does not
take place until careful preparation has been made. Their
green colouring matter breaks up ; the part which may still
be useful to the plant drains into the stem, leaving little heaps
of yellow grains in the leaves. Or a special colouring matter
may be formed, which, united in various ways with the
materials of the dying leaf, gives the warm shades of red,
orange, and purple which make the woods so beautiful
in autumn. When all is ready, a layer of cork (Fig. 41, C)
forms at the junction of the leaf stalk and the twig so that
no raw wound may be left ; the leaf-base splits across, just
above the cork layer, and the leaf flutters to the ground,
there to rot jind make rich leaf mould.

The leaf scats. — The former position of each leaf is now
marked by a curved scar {Is. Fig. 34), and a row of brown

AN INTRODUCTION TO NATURE-STUDY

U-ast Seasons
[ groVth .

dots (v.if,) in the scar still shows where the food-^ipes bent
outwards from the twig into the leaf. A line (a) .stretches
across and joins the two scars ol^aQh pair.

/V ^ * The buds. — Just above every

/^Bud for next * .1 u j u* u

^ Seasons growth. scar IS the bud which arose in

the axil of the fallen leaf. It is
.1 covered \^ith overlapping scales

of light green colour. At the

|tjr end of the twig is a single

^ terminal bud, similar in appear-

ance to the axillary buds, but
of larger size. It is instructive
/} terminal bud of

if a twig to pieces. The outer

\ ljj| scales are tough and green,^

while the inner ones are thinner
and have a beautiful silvery
appearance. Usually there are
fourteen scales. .Each is long
and narrow and bears at its
^ iPft ' T upper end the rudiment of a

leaf blade, which cannot usually
Growth of be seen well without a lens.
jSsaso^ before scale is really a leaf which

Fro. 34.-sycamo,e ,wig „> winter, ^as becn arrested in its develop-

/.jr., leuf-scars ; zk / k , ends of loot!- mcnt.
pipes ; A’, rings of .scars left by scales

ofla.st winter’s terminal buU. (Slightly When all the SCaleS haVC
reduced.)

been removed, there remains a
tiny tuft ,of delicate green foliage leaves surrounded by a
little down. Each leaf is folded fanwise, both for con-
venience of packing, and to protect its tender tissues from

j Growth of
; Season before
! last.

Fig. 34. — vSycamoip twig m winter.

the cold and the damp when the bud is expajiding. The
complicated folding of these leaves is well shown in Fig, 35,
which is a magnified sketch of a cross section through a

STRUCTURE AND USES OF BUDS

Fig. 35. — Cross section of a
Sycamfte bud. (X7.)

The

sycamore hud. The large sheaths surrounding the young
leaves ar^ four of the overlapping
scales. * In a large terrjiin:ft bud
a bunch of green flowers fnay
often be found.

The bursting of the buds. —

About the middle of April the
tree wakens to new*’ life. The
stored food makes its way to the
terminal buds ; invigorated by the
rich sugary sap the young leaves
swell and push forward, burst apart
the scafes, and open out their
folds to the light and air, as if
eager to get to work at the earliest possible moment.

scales fall off* to the ground, leaving close-set
rings of scars; the growing point elongates,
and new leaves — which were indistinguishable'
^in the bud — grow out and expand During
the summer, food is plentiful, and a little bud
appears in the axil of every leaf. Only with
the autumn does the activity of the tree
slow down. Except for some two pairs at
the tip, the newest leaves now remain stunted.
They form scales and close round the tender
growing point protectingly, in readiness for
the winter.

If necessary, the axillary buds could have
behaved as the terminal bud did, in which
case they would have grown out into side
twigs. They usually remain s^all, however,
, until next year (Fig. 36), for the leaves are
Fig. 36.— Syca- sb busy making food, and the terminal bud
ter.^^ is so busy growing in length, that no energy

AN INTRODUCTION TO NATUl^-STUDY

can be spared for their further development If any
accident had befallen the terminal growing point, onp or more
of the axillary buds would havlfcgr^wn out into side twigs.
Gardeners take advantage of* such reserve buds when they
clip off the ends of twigs to make a plant grow " bushy.”

A y^r’s growth. — When the bud scales drop oft they
leave, as we have seen, a series of closely-set rings of scars.

Fig, 37. — Horse Chestnut
twig in winter. ( x )

Fig. 38. — The teiminal part
of a Horse Chestnut twig in
winter. As., leaf-scars ;
ends of food-pipes. ( X ff )

The distance between one set of rings and the next (as at J?.,
Fig- 34)? therefore represents a year’s growth. The student
should get a twig two or three feet long and find out for him-
self, by examining the marks on it, what the twig did last
year, two years ago, and three years ago. With care he will
be able to say definitely in which year any fairly recent side-
twig began to grow out from its bud. ,

A horse chestnut twig. — A winter twig bf horse chestnut
(Fig. 37) is very similar in its general features to what we

STRUCTURE AND USES OF BUDS

have seen in the sycamore. The buds are in pairs at right
angles to, each other, and below each bud is a large corky
leaf scaV {/.s. Fig. 38), wjth ^e positions of the former food-
pipes marked by black dots These buds, however,

are larger than those of the sycamore, and each is covered
with a shining layer ot resin, to kee[) out insects and tlie rain.

We may slip the end of a })enknile under the bud scales
and remove them one by one. The first few are thin and
papery, and soaked in resin. Those next inside are woody
and much thicker. Next comes a layer of papery scales,
inside that a coat of cottony down, then another soft papery
layer, and lastly a thick pad of down. When we carefully
scrape away this down, we find — warm aivJ cosy in its midst
— a tuft of little objects with a most quaint resemblance to
hands clad in woollen gloves. We remove one of these, and
on scraping it gently with a knife we see that the “ hand ” has
seven fingers ; and it presently becomes clear that each
finger is a tiny green leaflet folded on itself, ancf that the*
hand is a youqg leaf. If we take off these gloved leaves in
turn one by one, we find as we proceed that they become
smaller, until they arc almost too small to be distinguished
in their fluffy nest. And when all the down and the baby
leaves are scraped away, the tender growing point of the
twig is left alone at the summit of a little cone, with steps
showing where the leaves were.

Had the twig been left undisturbed on the tree, the bud
would have awakened in spring and begun to grow (Fig. 39).^
The scales and the down would have been shed, leaving
only the rings of scars as a memento of the winter sleep ;
the growing point would have pushed on and on, lengthen-
ing perhaps a foot or more in three weeks ; the leaves would

^ In a large ternjinal bud the cone often ends in a tiny pink spray,
which gives rise to a branch of beautiful flowers when the bud unfolds.
In this case no further growth of the main axis of the twig takes place.

AN INTRODUCTION TO NATURE-STUDY

have opened their bright green fingers to the spring air, and
begun their work (Fig. 40), only to cease when in the autumn
they too dropped off, and the mew buds tucked themselves
up in their beds to go to sleep. The leaves of the horse
chestnut fall off, as do those of the sycamore, owing to a

Fig. 40. — The later
development of the ter-
minal bud of the twii^ of
Figs. 37 and 3y. ( x )

“separation-layer” arising at the base of the leaf stalk
(Fig. 41), and in this case each leaflet also becomes
separately detached in the same way.

Other forms of buds. — Surrounding the young silky-
fringed leaves of the beech bud are several crimson mem-
branous scales which are really the stipules (p. 43) of
undeveloped leaves. The thin, soft parts of the leaf blade
are sharply pleated (Pig. 42) between the ^ide veins which
spring from the midrib.

STRUC'^URE AND USES OF BUDS

The way in which the branching of a tree depends on the
buds is well shown in a lilac. The terminal bud does not
usually develop, so that eachy^of the two lateral buds just
below grows out into a br^ch, producing the characteristic
‘‘forking.” In the lilac bud every gradation between
scales and ordinary foliage leaves may be seen.

g. 41. — Longitudin.il section of
twig of Sycamore. A , base of leaf ;

Bs axillary bud ; C, cork layer. ( x 2.)

(From a photograph by Mr. A. Flat-
* ters.)

In the violet bud the two margins of the leaf are rolled
inwards towards the midrib ; while in the dock they are
rolled backwards.

Voi^ng fern leaves (Fig. 146) are not folded from side to
side like the examples referred to above, but are rolled into a
tight coil from apex to base. It is the upper surface of
the leaf (frond) which is to the inside. As the leaf grows,
the coil straightens out.

Fin. 42. — Cross
section through leaf-
bud of Beech . ( X 6. )

EXERCISES ON CHAPTER IV.

1. Where and when are the buds of common Enj^lish trees formed ?

(1901)

2. Show, by describing and drawing one example, that the branch of

a tree may preserve a record of past seasons in the bark. (1901)

3. Draw an unopened bud of sycamore. Of what parts is it composed,

and how are the parts arranged? (1901)

4 - What can be seen inside a large bud of horse chestnut ? On what
part of the branch are the largest buds to be found ? (1S9S)

N.S. E

AN INl'KODUCTION TO NATUKE-STUDY

5. Upon what does the method of branching of, a tree depend?

Give examples. ,

6. Examine pollarded trees ; what is the cause of theii; peculiarities ?

7. Examine buds of various t'fees jn s))ring, and try to* discover in
which cases the bud scales ^are (a) moditications of entire leaves,
(/j) modified leaf stalks, and (c) modified stipules.

S.'t^xamine and describe the method of protection, during the summer,
of the axillary buds of the jilane.

9. Take a poplar shoot during late su^mner, and examine the corky
separation-layer harming at the base of each leaf. Write an account of
its use, and make drawings of its ajipearance.

10. The “heart” of a cabbage or lettuce is of lighter colour, sweeter

taste, and more tender texture than the external leaves. How do you
explain these differences > (King’s Schol., J902)

11. Describe and explain the effect of clipping a privcHiedge.

12. (live an acrount of the changes in appearance in any common

leaf during the whole period of its growth.- Explain briefly what part
the leaf plays in the life of the plant. (Certificate, 1904)

13. Exiilain precisely how you would decide whether a given speci-
men consisted of (a) one compound leaf, or (/^ a twig bearing several
simplejeaves.

CHAPTER V.

HOW STEMS DO THEIR WORK

11. THE DUTIES OF STEMS.

1. The shapes of steins. ---Cut across a deaclncttlc stem and
a wallflower stem and examine the shape of the sections. The
former is square, the latter is five-ribbed. Is there any relation
between the form of the stem and the arrangement of the
leaves ?

2. The “bleeding’” of stems. — Cut through the lowe^ part of
a scarlet-runner^ plant in spring. Can you see any water
escaping from that part of the stem still in the ground ? Similarly,
cut back a sunflower stem when it is from i to i inch thick.
Does the water exude from all parts of the cut surface equally,
or does it come from definite channels ? To see this better, dry
the cut end with blotting paper and examine the surface wath a
lens. “Bleeding” is best seen in vine stems ; if a young vine
is available, cut it back in spring and observe the large escape
of water.

3. The ■water-current travels along definite channels. — Colour
some water with red ink and put in it the stalks of cut white
flowers such as snowdrops or narc jj^IT ”The stalks and flowers
soon becornc \"mned~Tvith red. Cut the stalks across and see
that the strands in the interior arc also coloured. The coloured
water has evidently travelled along definite channels.

4. The food-ckannels in a soft stem.— (<'/) Take a stout piece of
the stem of a deacfnettle, including three nodes (p. 45), and slit
it down in a line betw^een the end pairs of leaves. Then boil

AN INTRODUCTION TO NATURE-STUDY

the stern in water until the internal tissue is soTt. Take the
stem out and carefully scrape away all the soft material until
the woody strands can be W7II seen. These are the food-
channels. Notice their arrangement in the stem, and the
manner in which they run out to the leaves.

(Jb) rimilarly, examine the strands in a piece of sunflower stem,
and in an old cabbage stalk.

5. The path of the water-current in,, a woody stem.— Take a

leafy twig of elder or laurel and, from the part of the shoot
below the leaves, remove a ring of about an inch of the bark and
the soft tissues which lie beneath it, so as to expose the wood.
Put the end of the twig (below the ring) in water. The leaves
remain fresh and crisp, showing that the water travels either
along the wood or the pith, or along both. t

6. The water triivels along the wood. — l^ut a similar leafy twig
of elder dipping in water which has been coloured by red ink.
Expose to sunlight, and after an hour or two cut open the twig
and observe wliich parts are coloured. The bark and the soft
tissues between it and the wood are not coloured. The wood is
stained red. The pith is not coloured.

7. The path of the leaf-made food. —(a) Take a leafy branch of
a tree — e.g. willow — and near the bottom remove a ring of the
bark and the soft tissues lying between bark and wood. Put the
twig in water, so that the ringed part and a few inches above
shall be immersed. After a time roots are produced above the
cut. If any arise from the stripped part they are few in number
and much shorter than those above.

(6) Place a similar but uninjured twig in water, and notice
that the new roots are produced at the end. What is the reason
for the difference ?

The duties of steins. — No one can study leaves without
being impressed by the great importance to the plant of the
work which they do. Even the casual observation that
year after year thousands of fresh leaves mal^e their appear-
ance would indicate this. And when tt is learned that
throughout the day every leaf is busily engaged in decom-

THE DUTIES OF STEMS

posing carb( 5 n dioxide, and joining up the carbon with the
water and 'mineral compound.^ which have come up from the
root — thus forming sugars, starch and a host of other
valuable substances — some general idea is obtained that the
trunk and spreading boughs of a tree may, after all,^be of
minor importance, and may exist mainly to help the leaves
to perform their duties %s perfectly as possible.

This is the true view to take of the stem and its branches ;
their duties are (i) to bear the leaves and spread them out,
so that these will receive as much sunshine and fresh air
as possible ; (2) to supply the leaves with the water and
mineral stibstances which they require for their work ; and
(3) to receive from the leaves and distribute to the rest of
the plant the food materials which the leaves have prepared.
• A stem, together with the leaves and branches which it
bears, is called a shoot.

It will be found that almost all the variationj; in the
structure and habits of stems are connected with the
arrangements of the leaves. For example, the weight of the
mass of leaves borne by a forest tree is very great, and they
offer a great resistance to the wind ; the trunk and its
branches, therefore, are correspondingly strong and stout.
Again, when a stem is ribbed or ridged in any particular
manner it will generally be found that the ridges have a
definite relation to the leaves and to their points of insertion
on the stem. This has been seen (p. 44) to be the case in
the stem of the wallflower.

The tip of a stem or branch is occupied by a bud. As
the tip elongates (Fig. 40), the outer leaves of the bud become
separated by internodes, and new leaves continually arise
around the growing point.

The path of tie water in the stem. — It may easily be
shown that water travels up the stem to the leaves. It
is common knowledge that slightly withered leaves or

AN INTRODUCTION TO NATURE-STUDY

flowers become fresh and crisp again if the twig or stalk
is put in water. If the stalks of white flowers — say snowdrops
or narcissi — are put into water ioloured with red ink, the
flowers become veined with red, and, if the stalks are cut
intOj'Yed strands may be seen. This experiment not only
shows that water has travelled up the stalk, but it also shows
that the water has passed along ddiinite channels. When a
vine stem is cut back in the spring, the water wells out
rapidly from the end of that part of the stalk which is still
in the ground. This bleeding, as it is called, may also be
seen, though to a smaller extent, in stems of sunflower,
scarlet-runner, and other plants. By drying the cut surface
with blotting paper, and then examining it with a lens, it
may be seen that the w^ater escapes from the ends of certain
little tubes ; and it is possible in a boiled or rotting stem
(Expt. 11 , 4) to follow the distribution of the strands con-
tainingahese tubes. 'I h e strand sjiLauahpig tine length of the
s tem, outsid e the pith . Cross strands connect the main ones,
chiefly at the leaf-levels (nodes) ; and other strands run out
into the leaves to form the veins.

The tubes which convey the water current are in that
part of the strand which is nearest the pith, and they become
woody. Thus, if the current year’s growth of, say, a horse
chestnut or an elder twig is cut across, a thin ring of wood is
seen surrounding the soft pith. Outside the wood are the
softer tissues, surrounded by the bark. A ring of the bark
and soft tissues beneath it may be entirely removed from a
growing twig, leaving the wood exposed, but the leaves above
remain crisp and fresh, showing that this treatment has not
interfered with their w^ater supply. The water, therefore,
travels along either the wood or the pith. That the wood
and not the pith conducts the water may* be shown by
putting a leafy twig in water coloured with red ink. Only
the wood is stained.

THE DUTIES OF STEMS 71

The path of the food made by the leaves. — The plant
food whiQh*the leaves make is drained off into the stem, and
distributed to the parts wlme growth is taking place. This
food travels in the soft tissue — cal led the bast— which lies
below the ^ark.^ This fact can be shown indirectly by
removing a ring of bast from the lower part of a branch,
say of willow, and puttii^g the branch into water. When at
length the cutting puts out roots, these spring from the top
of the ring. If any s[)ring from the stripped part they are
markedly smaller, and fewer in number. In an uninjured
cutting, which is of course supplied with prepared food along
all its length by the bast vessels, such roots spring from the
cut end. 1'he supply of leaf-made food caft also be cut off
by ligaturing a twig below the leaves, as by twisting a wire or
c(»rd tightly round it. In such a case growth usually ceases
in the part of the twig below the strangled part, while
the upper part of the twig, to which the leaf-made Jbod is
now restricted, grows much more luxuriantly than before.
Gardeners often* produce unusually fine fruits by ligaturing
the lower parts of the twigs on which the fruits are ripening.

12. HOW STEMS AEE STRENGTHENED.

I. The formation of wood. — (i.) In summer take a horse
chestnut twig of thret^ or four years’ growth. Cut through it
with a sharp knife at the following places, and trim the cut ends
flat ;

(a) Near the apex ;

{h) at the middle of the current year’s growth ;

{a) about the middle of last year’s growth ;

{e) „ „ the previous year’s growth.

Make a drawing «f what you see in each case: —In {a) the
twig is covered on the outside by a green s/cin. In the middle
is the soft/zV/5. Between the two is a ring of separate strands.

AN INTRODUCTION TO NATURE-STUDY

In {b) and (r) the strands have joined up, and a distinct,
though thin, layer of wood surrounds the pith. Bas^ and other
soft tissues lie between the wdbd jjnd the bark, {d) has two
layers of wood, {e) has three* layers of wood.

(ii.) Split each length longitudinally. Why is it easier to do
this tflkn to cut the twig across? In which direction does the
grain of the wood run ? Make out in each piece the pith,
strands, or layers of wood, bast, etc., ait^ skin or bark. You can
tear off the bast in ribbon-like shreds. See how the strands
run out into the young leaves. Cut lengthwise through the
junction between the main twig and any side twigs, and notice
that corresponding parts are continuous.

2. The strength of a grass stem. — Notice the relativ^y
enormous strengtlj of a straw and other grass stems.

Burn a straw and observe the tube of mineral matter which is
left behind. Examine a piece of bamboo ; is it hollow or solid?

Woody stems. — To enable them to bear the weight of
the lea^4es and branches, and to withstand the force of the
wind, the stems of plants are strengthened in various ways.
Most commonly this is effected by the formation of wood in
the walls of the water- vessels.

Even in succulent stems, such as that of the sunflower,
the strands of vessels are stiffened by the long and narrow
wood pipes which run along them ; and when the strands
join up to form a complete cylinder a very strong column is
the result. Engineers make use of the same device,
knowing that the same amount of material will bear a far
greater stress when made into a hollow cylinder than it will
in any other form.

The thickening of woody stems. — In dicotyledons
(p. 23) and gymnosperms (p. 163) the cylinder, which is
formed by the joining-up of the conducting strands,
consists of three layers. The innerrposf of these is
the wood, and the outermost is bast. Between them is
a very delicate layer called cambium, which is continually

HOW StEMS ARE STRENGTHENED

dividing ancj forming more wood on its inner side and more
bast on its outer side. The wood is hard and resists
pressure, while the ba^yt is
soft and is squeezed against
the inside of the bark by the
expanding wood (Fig. 43).

The formation of nejr wood
and bast takes place vigor-
ously during the summer, at
the expense of the food which
is manufactured by the leaves
and travels along the bast
to the active cambium. As
autumn comes, the activity
Qf the tree slows down, and
the new wood is formed of
closer texture. In winter the
process stops altogether; but
with the warmth and the
plentiful food-supply of spring
the formation of new, open-textured wood is resumed.

This difference in texture between the autumn wood
and the later spring wood is quite visible to the naked eye
(Fig. 44), and gives rise to a series of annual rings, each of
which represents a year’s growth. Thus, a cross cut through
the four year old part of a branch (Fig. 43) shows four
layers of wood, one of which was formed each year. The
length formed last year has two layers of wood (if we look
in summer), and the current year’s growth has one layer, all
of which has been formed since spring.

The advantages of secondary thickening. — The forma-
tion of secoi^dary wood and bast is very important. The
new wood is required (i) to provide additional water-vessels
to supply the demands of an increasing number of leaves,

Fic. 43.~Portion of a four-year-old
•stem of the Pine, cut in winter, i, 2,

3, 4, the four successive annual rings of
tile wood ; l)ast ; b 7 \ bafk ; c, cam- '
hium ; /, spring wood ; /, junction of
wood of successive years ; pith ;
Wi, medullary rays; autumn wood.
(X4.)

74 AN INTRODUCTION TO NATURE-STUDY

and (2) to give the necessary increase of mechanical strength
to the growing tree. Again, the increase in the q-iiantity of
food manufactured by the leaves makes a larger quantity of
bast necessary for its distribution. Last of all, new tissues
are re(^uired to take up the duties of those which are old
and worn-out.

In forest trees, the central pith becomes almost obliterated
and the old stem practically consists of wood, bast, and
bark. The various annual rings, and the bast, of a woody

Fig. 44. — Cross section of Larch stem, showing annual rings.

Stem are joined together by a number of radiating horizontal
spokes called medullary rays (Fig. 43, ms^ ?fis\ ms\ ms").
These conduct water and food materials across the stem
from layer to layer. The beautiful lines and patches called
“ silver grain,” which may be seen in oak furniture, consist
of the medullary rays exposed in radial-longitudinal section.

Bark. — The very young stem is surrounded by a thin
waterproof skin, perforated by stomata (p. 53) as the skin
of a leaf is ; and the part immediately below the skin
possesses leaf-green, and can therefore decotnpose carbon
dioxide as a leaf does (p. 51). An old stem, on the other
hand, is covered by a layer of tough bark {dr, Fig. 43), which

CLIMBING STEMS

splits from lime to time, owing to the stretching which is
caused hy*the increasing thickness of the wood. The bark
begins as a layer of cork,*which^ forms on the outer side of
the bast. The cork cuts off the food supply from all the
external tissues, which die. Bark, therefore, consistsj(©f the
cork and the dead layers outside it.

Grass stems. — The# great strength of grass stems — so
apparent when we try to bend a straw — is largely due to
silica^ the substance of which rock-crystal and ordinary sand
are composed. When a straw is burnt, this remains as a
hollow cylinder of mineral matter. The great strength of
the cylin(irical form has already been referred to. It is very
well seen also in a bamboo stem, and •anyone who has
blunted the edge of his knife on a piece of bamboo will
appreciate the additional hardness which is given by the
presence of mineral matter.

13. CLIMBING STEMS.

1. * Hooking stems. — Examine a bramble or a wild rose plant
in a hedge. Why docs it need to climb ? How does it climb
Pull a branch and notice by what means it resists the pull.
What is the shape of the pricklesl Do they point upwards or
downwards ? On what parts of the plant are the prickles
found? Notice how easily a prickle may be pushed off, side-
ways. Is it as easy to tear it off lengthways? Is the prickle
a little branch, or merely an extension of the rind ?

Contrast a prickle with the thorn of the hawthorn. The thorn
does not come off easily, and it contains a woody core which is
continuous with the wood of the branch. Cut lengthwise
through the thorn and the branch which bears it to see this.
The thorn is a short pointed branch ; it arises in the axil of a
leaf, and sometimes bears leaves itself.

2. The ivy.— Observe how the climbing stem of the ivy is
attached to a wall or tree. It puts out a line of roots on its

AN INTRODUCTION TO NATUUE-STUDY

The differences between such a prickle and'^a tnorn like
that of the hawthorn should be carefully noticed. , A thorn
is really a little twig which hail reipained short and become
pointed at the end. It hak a core of wood which is con-

Fig. 46. — Climbing stem of Fig. 47. — Climbing stem of

Honeysuckle. (xF) Convolvulus, (xj.)

tinuous with the wood of the branch bearing it. That a
thorn is really a little branch is shown by its origin in the
axil of a leaf, and by its often giving rise to leaves and
buds.

The stem of the ivy climbs by means of little roots, which
it puts out on the side furthest from the light (Fig. 45),

CLIMBING STEMS

These give. out a sticky liquid which, on drying, cements
them to thd wall or tree.

Twining? stems are much, in advance of these. There
seems to be something approaching intelligence in the
manner in which the young stem of a hop, honeysuckle,
or convolvulus, which at first grows straight up, bc^ns to
wander round and round, tracing a spiral path in the air
until it touches a supf)ort. Then, however, as if the plant
could feel, the movement below the point of contact stops ;
but the upper part of the stem still revolves and therefore
twines round the support. The stems of the honeysuckle
(Fig. 46) and the hop turn in the same direction as the
hands of^a clock. This is called the ‘‘ clockwise direction.
On the other hand the convolvulus (fig. 47) and most
other twining stems are “ counter-clockwi.se ” climbers,
^he stem of the bittersweet revolves indifferently in either
direction.

Sensitive clasping organs in their simplest form arg seen in.
the hvbiing leaf stalk of the clematis and tropceolum ; the
stem itself revolves as if to give its leaf stalks every oppor-
tunity of finding suitable supports. The leaf stalks seize
these and twine round them.

Most wonderful of all climbing organs are the tendrils.
They are well seen in Fig. 48. A part of the plant — some-
times a leaflet, as in the pea (Fig. 28) ; sometimes a
branch, as in the passion flower ; or a flower stalk, as in
the vine — becomes modified into a thread, slight but strong.
When the end of the thread touches and then twines round
a support, the whole tendril forms itself into a spiral which,
like a wire spring, draws the plant up to the support, and can
yet lengthen and yield to the wind when necessary. In the
middle of the tendril the direction of the spiral is reversed,
so that the* tt;ndril can be straightened without being
twisted.

AN INTRODUCTION TO NATU^RE-STUDY

The tendrils of the Virginian creeper do not twine, but on
meeting a wall they form round red suckers at the end, and
attach the plant (Fig. 49). ^ • r

Fir,. 48.— Flow a tendril grasps a support. The spiral is
reversed at x.

• Fig. 49. — Virginian
Creeper. A’, stem ten-
drils. (x^.)

14. CREEPING AND UNDERGROUND STEMS.

1. A creeping stem. — Examine a plant of the ground ivy. Is
the stem strong enough to stand upright? How does it spread
out its leaves to the light and air ? The stem grows along the
ground, and at intervals it give? off a pair of leaves which grow
upwards, and a tuft of roots which grow down to the ground.

2. A runner.— Is the ^‘runner” of the strawberry qf the same
nature, ix. is it a continuous stem like that of the ground ivy ?
When the plant is carefully examined, the creeping “ stem ” is
seen to be a branch arising in the axil of a leaf. The branch
runs along the ground for a little distance, and then roots itself
and gives off a number of leaves. In the axil of one of these

underground stems

another branch arises and runs on in the same direction. The
same branch does not run on and on.

3. A Btpldn. — Follow carefully^ the underground part of the
couch grass and make out ks connection with the main shoot.*
It is a branch like the runner of the strawberry, which arises in
the axil of a leaf, and extends only to the next shoot. ^

Compare the stolons of the cinquefoil.

4. A potato tuber. — Examine a potato tuber (the part which is
eaten). Notice the “eye 5 .” These are buds, with scale leaves.
Leaves never occur on roots, so that the potato must be an
underground stem. Put a pin into every eye, and wind a thread
round the tuber along the bases of the pins. It forms a spiral.
Cut the potato into halves, and pour a drop of iodine solution on
the cut surface. What is the meaning of the blue dots which at
once make their appearance ? Plant a potato in warm, moist
earth, and when it has sprouted notice that each bud (eye) has
given rise to a branch.

*5. Bulbs. — Cut an onion or snowdrop bulb down the middle,
and draw what you see, marking on your drawing the outer
scale leaves, the swollen bases of last year’s leaves, th^ young
leaves in the middle, the short, thickened stem, and the roots.
Also cut other bulbs across and again draw. What is the
similarity and what is the difference between these bulbs and
such a bud as a cabbage ?

Also examine hyacinth, tulip and daffodil bulbs. Put them in
glasses with water touching their bases, and watch them grow.
What do they live upon ?

6. A crocus corm. — Obtain a few crocus “ bulbs ” in the early
winter. Observe the tough outer tunic springing round the edge
of a circular scar on the base. If there are any roots they come
off from the scar. Take off the tunics from one “bulb” and
observe the bud or buds at the top of the white mass inside.
Other tunics cover the buds. Cut lengthwise through the mass
of the “ bulb ” so as to bisect the largest bud. Separate the
parts of the bud with a needle and notice (f'?) the thin outer
leaves, {b) the young foliage leaves, (r) the flower-^eath and
flower. Pour a drop of iodine solution on the cut white mass
(the, stem) below the bud. It turns blue. Why?

N.S. F

AN INTRODUCTION TO NATURE-STUDY

What is the principal difference between a Crocus “bulb”
and the bulb of an onion, hyacinth, or tulip? A true bulb is
mainly composed of swollen leaves or leaf bases ; in the crocus
the thick, rounded stern makes up niost of the bulk. It is better,
therefore, to speak of a crocus cortn^ to indicate the difference.

Plant the remaining corms and examine them at intervals for
a year. ' Notice the formation of the roots, the lengthening of
the buds, the formation of the flowers, the activily of t/iefoliaye
leaves after flowering (why?), the withering of the roots and
leaves in summer, and the growth of the enlarged base of the
branch into next year’s corm.

Creeping stems — - Instead of climbing, many stems find
that the best method of spreading out their leaves is to

creep along or under the ground, and give off leaves and
roots at intervals. Not only does this device prevent the
leaves of one node from interfering with the light and air
supply of those of the next, but the plant is continually
coming in contact with a fresh lot of soil. The ground ivy
is an instructive example of this method of growth. The stem
creeps along the ground, and at every node it gives oft a
pair of leaves which grow u{)wards, and a tuft of roots
which grow down into the ground.

The runner of the strawberry (Fig. 50) appears at the
first glance to grow in a similar manner.^ As a matter of
fact, however, the apparent stem is a branch arising in the

UNDERGROUND STEMS

axil of one of the leaves of the last node. The branch
runs alo^ig* the ground and gives rise to a new shoot, and
from this another branch, aii)ringing
from the axil of a leaf, forms
another runner. The same branch
docs not run on from shoot to
shoot. •

The stolon of the couch grass
(Fig. 51) is somewhat similar.

The erect stem of the plant is
divided, as usual, into nodes or
knots (fr®m which the narrow,
sheathing leaves arise) and inter-
nodes. Branches (stolons) si)ring
ie the axils of the lower leaves,
turn downwards, and run on fig. 5i.~Stoion of Couch
underneath the soil, taking root
again at some distance from the parent plant. *

Underground* stems. — Although the stem is usually that
part of the axis of a plant which is above ground, there are

Fig. 52. —Creeping underground stem of Solomon’s Seal, bud of
next year’s aerial growth ; /?, scar of this year’s growth ; r, d, e, scars of
aerial growth of previous years ; w, roots, (x ^.)

many exceptions. I'he bracken fern, daisy, coltsfoot,
Solomon’s seal (Fig. 52), and many other plants have stems

AN INTRODUCTION TO NATURE-STUDY

which are ordinarily buried in the ground, giving off leaves
above and roots below. In some cases such underground
stems become much swollen wiih stored food-material —
manufactured by the leaves in excess of immediate require-
ment'!. In the potato, for example, certain underground
branches of the stem store up starch to such an extent that
their ends become fleshy, ovoid masses some inches in
thickness (Fig. 53). The true nature of these tubers is
revealed by the buds or “ eyes ” which spring upon them.

The buds are arranged spirally
— as may be seen by sticking
a pin into each ai?d joining
up the pins with thread — and
when the tubers are kept in a
warm, moist place, each bud
grows out into a new leafy

The structure of a biUb is

Fir.. 53-Par. of a Potato plant, easily made out in the onion,
showing the oM tuber (dark) and tulio (Fig. Ka), hvacinth, Of

daffodil. Wlien such a bulb is
cut down the middle, it is seen to be mainly composed of
leaves or leaf-bases, swollen with stored food. Inside these
are the young leaves and the flower bud, which would have
expanded next season ; and on the outside are a few thin scale
leaves. All these leaves spring from a fleshy button at the
base, which gives off roots below. The button is the flattened
stem. When a plant produces a bulb it will generally be
found that it flowers either very early or very late in the
season ; that is, at a period which would not be very
favourable for the work of the leaves. The flower

Fig. 53^ — Part of a Potato plant,

(E^ig. 55) is produced at the expense of the stored food
in the bulb — made in excess of the requirements of
the previous season. After the plant has flowered, the

UNDERGROUND STEMS

new leaves Work until they have made enough food for
next season’s flower, and then they also die.

The s6-called bulb of the circus is technically known as
a conn (Fig. 56). It differs from a true bulb in consisting
mainly of a fleshy, rounded stem in which the surplusy'ood

Fig. 54. — Longitudinal
section of Tulip bulb, zk,
modified stem ; js.v, scale
leaves ; if, terminal bud ;
young bud ; w, roots. ( x i )

Fig. 55. —Daffodil. (X ^.)

made by last year’s leaves is stored up. The plant is thus
able to flower early, without waiting for the new leaves to
supply food. The swollen stem bears one or more buds,
and the whol^e is surrounded by tough tunics of scales.
When the cofm begins to grow, roots are put out from «the
base, and the flowers and— later — the leaves of the buds *

AN INTRODUCTION TO NATURE-STUDY

expand. The foliage leaves continue theif work after
flowering, and the food which they make accumujates in the
base of the former bud, which becomes swollen to* form the
new corm for next year’s flower. The leaves then die
dowp, their bases becoming the tunics of the new corm.

FiCi. 56. —Crocus corm, seen from the side, from below, and in longi-
tudinal section, c', base of bud, which will grow into next year's conn ;
/dXh., food channel ;y/r, flower bud; /, young leaves; roots;

Uinics. (x^.)

EXERCISES ON CHAPTER V.

1. Mention experiments, wliich prove that organic substances are

formed in the leaves, and distributed to other parts of a green floweiing
plant. Ry what channels are they distributed ? (1^95)

2. Draw a cross section through the stem of a fliiwering ])lant selected
by yourself. Explain the uses of the chief things seen in the section.

(1S97)

3. Mention experiments or observations which sliow hy what tissues

water ascends to the leaves, and nutritive substance descends from the
leaves. (1S97)

4. By what tissues does water pass along tlie stem of a tree to the

leaves? Give proofs, of your statements. {1898)

5. Desciibe the effect of a tight ligature upon a growing hazel stem.

(1898)

6. What proofs can V>e given that the stem of a tree draws nourish-
ment from the leaves ? (1898)

7; Show, by describing and drawing one example, that the branch of
a tree may pre.serve a record of past seasons in its wood. (1901)

EXERCISES

8. Mention aft experiment which shows that organic substance formed

in the leaves travels down the stem outside the cambium. (iQOl)

9. Obtaki *11011 sections pla^e-shavings) of as many different

kinds of wood as possible, and* gum them into a book, writing under
each section the name of the wood and the direction (transverse, radial-
longitudinal, or tangential-longitudinal) of the section. ^

10. Make yourself familiar with the appearance and characters of the
different kinds of timber used in carpentry and joinery.

11. Notice the light-browt spots on the bark of twigs of apple and
horse chestnut. These are called Icnfiteh ; they are breathing-pores.
In how many other trees can you find lenticels ?

12. Observe whether an ivy stem puts out roots only where they can
become fixed to a support, or indiscriminately.

13. Make a list of plants which you have observed to climb by twin-

ing stems, aitd note whether they are clockwise or counter-clockwise
climbers. •

14. Make careful drawings of all the tendrils you can find, and try to
discover which pait of the plant has been modified to form the tendril.

15. (lently stroke a tendril of the passion flower and write an account
of any resulting movement.

16. Mention any three climbing plants which grow wild^ in this

country, and explain in each case how the plant climbs. (1895)

17. What is the •difference between {a) a thorn, {()) a leaf-spine, and

(r) a prickle? (live examples. (1896)

18. hmumcrale and briefly describe the principal varieties of tendrils,

and explain how they act. (1897)

19. If a wire is fastened tightly about a growing branch of a common

Uee, and left foi two or three years, what effect will he produced, and
how can the effect he explained? (1904)

20. What processes of vegetable growth are accompanied by the

l^rcseiice of sugar? Give examples from plants within your own
experience. (King’s .Scholarship, 1904)

21. What are the chief uses of the vessels of a herbaceous stem?
Mention observations nnd experiments in support of your statements.

(1905)

22. How can you demonstrate experimentally that food .substances,
formed in the leaves of a tree, descend to the branches below? (1905)

CHAPTER VI.

SOME COMMON FLOWERS.

15. A TYPICAL FLOWER.

I. The wallflower.-- After noticing the general habit of growth
of a wallflower plant (Fig. 57), and especially the shape ard
venation of the leaves, make out the following parts in one of

its flowers. On the top
ol the flower-stalk (called
the receptacle^ are :

{a) Four small, narrow,
purplish leaves, called
sepals. The four sepals
together constitute the
calyx. Take off the se-
pals one by one. Notice
that two opposite se-
pals are bulged out at
their bases, forming
pouches containing nec-
tar. Try to get out a
small drop of nectar on
Fig. 57.— Wallflower, (xj.) the point of a pencil and

taste it.

ifi) Four showy leaves arranged in the form of a Maltese
cross, called petals. They are yellow, or red, or purplish in
colour, are delicately scented, and have beautiful velvety surfaces.

A TYPICAL FLOWER

«9

The four petals together constitute the corolla. Take off the
petals one one.

(r) Six stamens, each consisting of a greenish stalk or filament
surmounted by a yellow, boat-shaped body, called the anthen
The anther is a four-chambered box containing an enormous
number of tiny yellow grains called pollen grains. Two JT the
stamens are shorter, and are fixed at a lower level on the
receptacle than the remai^iing four. Take off the stamens one
by one.

{d) A central pistil^ shaped somewhat like a slender bottle.
At the top, where the cork would come in a real bottle, is the
notched slig^ma, slightly sticky. The neck is called the slyle^
and the part corresponding to the body of the bottle is the
ovary. Te^ir open the ovary with a needle to see the ovules,^
which in an undisturbed flower would have bet:ome seeds.

Watch bees visiting flowers. Does each bee confine itself to
oiie kind (species) of flower at each journey, or does it visit
several kinds indiscriminately? Try to discover what the bees
are doing. Avoid alarming them.

•

The work of.flowers. — The roots, stem, and leaves of a
plant do a great deal of work, but, as it is performed for the
benefit of the plant itself, it is all, in a sense, selfish work.
Plants, however, like animals, grow old in time, and at last
die. If they are not to become extinct it is evident that
they must devote part of their energies to producing new
individuals, and to sending these forth into the world as
well equipped as possible for the battle of life. This un-
selfish and self-sacrificing part of a plant’s life-work is called
reproduction; in the higher plants it is carried out by flowers.

The structure of a wallflower blossom. — The flowers of
different groups of plants vary greatly in structure, but a
good general idea of the arrangement of the parts of
a flower can obtained by examining the blossoms of a
wallflower plant ^Fig 58). Other flowers may afterwards
be compared and contrasted.

AN INTRODUCTION TO NATJfRE-STUDV

There are evidently at least eight leaves in th'e flower, but,
unlike the green foliage leaves, these are no^ arranged
spirally, but stand at nearly •the^same level on the end —
called the receptacle — of the flower-stalk. The most ex*

Fig. 58. — Wallflower. branch, bearlnj^ leaves aiul flow'crs ;

/>’, flower; C, loin^itudinal section of flower; /^, st.unens and pistil;

Ji, fruit ; .S', transverse section of stem, (x i.) ^

ternal leaves are four in number, small, narrow, and purplish
in colour. Each of these leaves is called a sepal, and the
four sepals together constitute the calyx of the flower. I'wo
opposite sepals are pouched at the base, fotming pockets,
in which a sugary fluid, called nectar, •collects. Before
the bud opens, the calyx is the only part of the flower

A TYPICAL FI.OWER

which is visible. It is probably developed in the wallflower
solely for the protection of the more delicate structures
within. 'Next, inside thf sepals, placed alternately with
them, and standing a little hig*her ori'the receptacle, are
four showy leaves arranged in the form of a Maltese (J|^ss.
These leaves are called petals, and the four petals together
form the corolla. The petals are delicately scented, and
their surfaces have a beautiful velvety sheen.

When the sepals and petals are removed, there remain

standing on the receptacle six stamens surrounding a
centrally-placed pistil (Idg. 58, J)). The stamens are
the male ^art, and the pistil is the female part, of the
flower. Bach stamen con-
sists of a greenish stalk or
filament, surmounted by a
yellow boat- shaped body
called the anther. I'hc
anther is a box with four
compartments ,(Fig. 59).

When it is ripe, each com-
partment contains an enor-
mous number of tiny, yellow
grains called pollen grains ;
and when the anther bursts
(as it does as soon as the flower opens) its inner face is
covered by the yellow dust of the pollen.

rhe pistil bears a rough resemblance to a slender bottle,
and consists of three distinct parts. The neck of the
“ bottle,” called the style, is short in the wallflower, and
differs from an ordinary bottle-neck in being solid instead
of tubular. At the top of the neck, where the cork would
come in a regil bottle, is a body called the stigma. The
Siigma of the waWflower tustil is hairy, notched, and slightly
sticky, from the presence of a sugary solution which forms

Fic;. 5 Q. — Cross st'C'tion thiouRh ci Wall-
flower bud. sepals; petals;

anther of a long stamen; i/r.
anther of a short stamen; pollen

sacs ; w.illtjf ovaiy ; O?’/, ovule. (X8.)

AN INTRODUCTION TO NATURE-STUDY

upon it. The part of the pistil, corresponding to the body
of the bottle, is the ovary. It contains four rows of little
white ovules, which are destii'/ed to become seeds capable of
growing up and forfhing new wallflower plants.

The relations of the parts of the flower are well seen in
Fig. 59-

Fertilisation. — In order that an ovule may become a
seed, its contents must mix with the contents of a pollen
grain. The fusion of the two constitutes fertilisation. For
fertilisation to take place, the pollen grain must first of all
gain access to the stigma of the pistil. If this be prevented
the flowers will wither without forming ripe seeds. (This
may be proved easily by Expts. 18, 3 and 21, 2 .) The sugary
solution at the top of the stigma stimulates the pollen
grains to growth, and each puts out a long tube which
grows down the style. The living matter of the grains
keeps near the tips of the tubes as these continue their
journe^ down the style At length the tubes enter the
ovary and find the ovules. Each ovule has at one end a
minute pore (the micropyle— p. 6 ), and a pollen tube
finds this and enters it. The living matter of the pollen
tube fuses with that of the ovule in the neighbourhood of
the pore, and fertilisation is effected. It is now easy to
understand 1 |liat the comparatively insignificant stamens and
pistil are the all-important parts of a flower.

How the wallflower advertises.— Botanists have proved
that a flower produces more, and also better, seeds when it
is fertilised by pollen from another flower of the same
species. I’his is called cross fertilisa 4 iioii. The wallflower
relies upon bees for the transference of the pollen from one
flower to another ; and it is solely to attract them that the
petals are so delicately scented and brilliantly coloured, and
that sweet nectar collects in the sepal -pouches. The gaily
coloured petals are therefore advertisement placards which

TITE WALLFLOWER FAMILY

are hung out to attract the attention of bees. A bee comes
to a wallflower for the sake of |)oth nectar and pollen — the
“ bee-bread.” As the be(f thrusf.s its proboscis down be-
tween stamens and pistil in search of the sweet licjuid in the
pouches, its head is pretty certain to come in contact '^h,
and to brush off, some of the pollen dust hanging loose
on the inner faces of th* anthers. When the bee flies off
to another wallflower and continues
its search for nectar, it almost in-
variably leaves some of the pollen,
from the first flower, on the hairy
and sticky ttigma of the second.

In almost all cases when a flower
is brightly coloured it depends upon
the help of insects for cross fertilisa-
tion.

16. .THE wallflower
FAMILY.

1. Shepherd’s purse. — Compare the
bhe|)herd’s purse (Fig. 6o) with the
wallflower. The flower is very much
smaller, and white, but the parts have
the same arrangement as in the
wallflower, viz., four sepals, four petals
arranged in the form of a cross, L)
six stamens (two short and four long), and a central pistil,
all arranged separately on the receptacle. Look down the
plant, and notice that ^ in the oldest ( lowest) flowers, every-
thing but the pistil has dropped off, and that this has become
greatly enlarged to form a fruit. Cut some fruits open, both
lengthwise and crosswise, and observe that each consiks of two
pocket-like chambers, separated by a thin partition on which
the seeds are borne. Notice the manner in which the oldest
fruits have opened naturally.

Fic;. 6o.— SJiepherd'.s Purse,

96 AN INTRODUCTION TO NATURE^STUDY

of their first season. As these plants naturally flower in
their second year of growth and then die, tliey are called
biennials. The production of flowers and fruit k a great
strain on. a plant, and it is to prepare for the effort that
th7,J:urnip and radish store so much food in their roots
during the first year as to give them a globular and spindle
shape respectively. A carrot is not a crucifer, but it also
adopts this device. ^

The cabbage is grown for its leaves. Varieties of the
cabbage arc Brussels sprouts, broccoli, and cauliflower ; it is
the very small flower-buds of the last two which are eaten.
Cress and white mustard are eaten in the seedling stage.
The seeds of tlje black mustard are ground ana eaten as a
condiment.

17. THE BUTTEECUP FAMILY.

I, Tlie buttercup. — Notice the habit of growth, characters of
the leaves, etc. Is the buttercup a dicotyledon? Make this
observation with all flowering plants. (See, however, Chap. VI II.,
p. 163.)

In the flowers of a buttercup (Fig. 65) make out :

(a) The r^r/yx of five green, separate sepals ; they are the only
parts to be seen in young, unopened buds. Take off the sepals
of a fully-opened flower one by one.

(/y) The corolla of five, golden-yellow, separate petals, alternate
with the sepals. Notice the nectary — a little pocket — near the
base of the upper surface of each petal. Take off the petals one
by one and observe that they are fixed on the receptacle, a little
higher than the sepals.

{({') On the top of the receptacle the large number of separate,
flask-shaped bodies, which together make up |he pistil. Each
of these is called a cajpcl. •

Watch bees and other insects visiting buttercups and notice

THE* BUTTERCUP FAMILY

how they stand on the flower to obtain the nectar from the
nectaries. Does a bee on leaving go to another buttercup, or
does it chang’e to another kind of flower ?

In a flower from which the? sepals, petals, and stamens have
flillen, notice the compound /r/z/V (Fig. 66), consisting of ripened
carpels. Open a carpel with a needle and pick out the slfi^e
seed.

2. Other plants of the buttercup family^ — Notice that in the
anemone (Fig. 67) and marsh marigold (Fig. 68), the sepals
appear to be absent (the three leaves under the anemone flower
are not parts of the flower ; they are called brads). The
apparent petals are really the sepals ; it is the corolla which is
absent. Observe the large number of stamens, and notice that
the pistil consists of several separate carpels.

In what kind of ground have you seen thest? plants growing
wild?

The buttercup family. — The buttercup (i'ig. 65) and its
relatives resemble the crucifers (i) in being dicotyledons (as
is indicated (p. 40) by
the venation of the
leaves), and (2) in the
fact that, of the parts
which compose the
flower, each group is
arranged separately on
the receptacle. For ex-
ample, the stamens are
not connected with
either the calyx, the
corolla or the pistil.

Having noted these
points of resemblance, however, we are met by some
important differences. In the buttercup there are usually
five sepals and five petals ; there may be twenty or more
stamens ; and the pistil is not a single structure, but con-
N.S. G

AN INTRODUCTION TO NAIURE-STUDY

sists of a number of separate parts, each of tvhich is called
a carpel, and contains a single ovule. I'he^ pistil of a

crucifer consists of onl^ two car-
pels ; these are welded together
into a single structure, and until
the fruit ripens a slight notch in
the stigma is the only external
indication that the [)istil is in two
parts.

Insects visit buttercups for the
sake of nectar and pollen, and

Fig. 66. — a. Compound fiuit of
Butteicnp (XaP; a carpel
(X4); c, carpel in 'ongitudinal
section (X4).

whilst creeping about the flower
transfer pollen to the stigmas of
the carpels. T’he insects may

have brought some of this pollen from other flower.s, and

then cross-fertilisation is

caused. If the pollen
is dei ived from the same
flower self-fertilisation is
the result.

After fertilisation the
ovules become seeds ;
the sepals, petals, and
stamens drop off; and
the carpels swell up,
farming a dry com-
pound fruit (Fig. 66),
consisting of several
nutlets.

Two other common
plants of this family
are the anemone (Fig. 67)
and marsh marigold (Fig.

Fig. 67. — Ancftione. (x^.)

68). In neither of these cases has the flower any petals,

THE PEA FAMILY 99

but the calyx* has taken on the appearance of a corolla.
In the raafsh marigold it is ^large and yellow ; in the
anemo”'.e it is white or ptirple. • The three green leaves
immediately beneath the dower of the anemone are callg^
bracts. They should not be mistaken for sepals.

The plants of the buttercup family are as generally
poisonous as the crucifers are wholesome. Monkshood is

Fi(,. 68.— Marsh Marigold. (X^.)

especially poisonous, and its root has been mistaken, with
fatal results, for that of horse-radish. It is often noticed
that grazing cattle avoid the buttercups in a field. The
bitter and disagreeable taste of the leaves is of course a
valuable protection to the plant.

18. THE PEA FAMILY.

I. The garden pea.- -Notice n^ain the habit of the plant: its
compound, net-veined leaves with large stipules, and its method
of climbing by tcndiils which are modified leaflets. E.xamine
the flower and make out (^7) the calyx of five united sepals ; {b)
the curiously shaped corolla. The large upper petal is called

lOO

AN INTRODUCTION TO NATURE-STUDY

the standard^ the two at the side are the wings^ And the lowest
(really two locked together) is^the keel ; (r) the ten slamens. One
(opposite the standard) is separate ; the remaining nine have
the lower parts of their filaments united to form a tube. Slit
oite»> the filament-tiibe and remove the stamens, noticing how
they are attached to the other parts of the flower ; {cl) the pistil.
Slit open the ovary and see the ovules in it. Watch the various
stages of the formation of the fruit (pod).

Watch bees visiting the flowers. The insect alights on the
wings, and its weight pulls them down and lowers the keel,
bringing the stamens against the bee’s body.

Cut a complete flower down the middle with a sharp knife, and
notice that calyx, corolla, and stamens seem not to be inserted
separately on the receptacle, but to spring from' a common base.

2. Other plants of the pea family. — Examine also bean, vetch
(Fig. 69), meadow vetchling (Fig. 70), clover (Fig. 71), laburnum

JIIE PEA FAMILY

101

(Fig. 73), andjjroom. Com-
pare llie habite of growth of
the plants, , and notice that
they all have the sam^
peculiar shape of flower.
Dissect a flower of each.
Notice that in laburnum and
broom the ten stamens are
all united. In clover the
flowers are in heads. Notice
how the leaflets of the clover
plant close at sunset.

3. Fertilisation. — Dig up
several red^ clover plants in
early summer and pot them.
Cover about half the plants
with gau 7 .e, so fixed on wire
frames that insects cannot

Fig. 71. — Red Clover, (xj.)

Meadow Vetchling. (X J.)

get inside, and then put
all the plants tr^gether
where they will get plenty
of sun. Water them regu-
larly, and notice which
plants ripen seed. How
do you account for the
differences 1

The pea family. —

Plants of the pea family
are found in all ejuarters
of the earth. 'They are
of very diverse size and
habit of growth ; the
laburnum, for example,
is a tree ; the gorse is
a bush ; the brOad bean
has a strong, erect, her-

102

AN INTRODUCTION TO NAWRE-STUDY

baceous stem; the pea is a weak-stemmed climbing plant ; the
clovers are small herbs with flowers forming “lieads.” Most
of the members of the family agree in having d butterfly-
shaped” corolla (Figs. 72# and ^3), which consists of three
^^Jl-markcd parts, viz., a large standard, a pair of wings,
and' two closely-connected [)etals which form a boat-shaped
keel. There are ten stamens, and the filaments of nine of

€

Fig. 72. —Rinl’s-fool Trefoil, i, flowerin" Fig, 7^. — FloweriiiE; branch of Laburnum ;

branch ( X if) ; 2, (It)vvei ; pistil and htamens> ; s/, stiindard ; w, wintts ; k, keel ; i, 2, 3, the

4, pistil (xrj); 5, fruit (xjf); 0, corolla; llowei fi 0111 different pdiiUs of view, (x^.)

a, .standard ; k, wing.s ; i, keel ; 7, di.igram of
flowei.

these usually cohere to form a tube surrounding the ovary.

In the laburnum, gorse, and a few others, all the ten stamens
are united. When a bee visits the flower, in search of
nectar, it alights on the “ wings ” of the flower, and its weight
depresses these and pulls down the keel. The anthers of
the stamens are so placed with respect to the keel that this
results in a mass of pollen being scraped pff ‘the anthers and
forced out at the beak of the keel, or in the stamens being

THE ROSE FAMILY

103

suddenly liberated and scattering pollen on the bee. The
pollen sticks to the. bee's body, and some of it is almost
certainly tTahsferred to the stigrja of the next flower visited.
The quaint shape of the corolla is* thus definitely adapted to
the visits of insects ; for the nectar is so placed that Jp
obtain it the insect must carry off some of the pollen.

The calyx, corolla, and stamens are not obviously — as in
the wallflower and buttercup ~ inserted separately on the
receptacle, but seem to spring from a common base.

The fruit is a pod (Fig. 3), which opens when ripe
along both margins and liberates the seeds. Laburnum
seeds are poisonous, but the seeds of many other plants of
the family (peas, beans, lentils, etc.) are valuable foods.

. 19. THE ROSE FAMILY.

1. The wild rose (Fig. 75). — With a sharp knife cut verti-
cally through the middle of a wild rose. Notice th^at the
receptacle forms a deep cup, and that the carpels of the pistil
are enclosed in the cup. From the edge of the cup spring the
five sepals, five petals, and numerous stamens. What is the
great difference between a rose and a buttercup ?

Trace the formation of the succulent fruit or hip from the
receptacle cup of the flower. Cut through a rose hip, and
observe the ripened carpels in the interior.

2. The blackherry. — Similarly examine a blackberry flower
(Fig. 76). This is still more like a buttercup, but — as in the
rose and the pea — the calyx, corolla, and stamens seem to
spring from a common base, and not to be inserted separately
on the receptacle.

Trace the formation of the compound fruit, and notice that
each part is like a little plum or cherry.

3. The cherry. — Similarly examine cherry lilossom (Fig. 77).
The pistil consists of one carpel, and is fixed at the bottom of the
receptacle-cup, whiie the calyx, corolla, and stamens are fixed on
the margin of the cup. Trace the origin of each part of the fruit.

Compare the plum and apricot.

104

AN INTRODUCTION TO NATCJRE-STUDY

4. The apple and pear.

— Cut vertically through
an apple blt)&soni (Fig.
74) or pear blossom (Fig.
78), and notice that the
ovary is embedded in the
receptacle, and that calyx,
corolla, and stamens are
fixed on the lop of this.
Cut across the ovary and
see the five divisions (car-
pels).

The eatable part of the
fruit is the » swollen re-
ceptacle. Compare the
hawthorn.

The wild rose. — The

most commonly, woody
trees .or shrubs. The
leaves are provided with
stipules in nearly all
cases. The wild rose
(Fig. 75) may be taken
as a type of the group.

It bears a superficial
resemblance to a butter-
cup, but on dissection
considerable difference
in the arrangement of
the parts is seen. In
the rose, the receptacle
is urn-shapied ; from the
margin of the urn spring
the five sepals, five
petals, and numerous

plants of the rose family are,

F iG. 7^.— Wild Rose, ( X ^ )

^HE ROSE FAMILY

stamens ; while* inside the urn the separate carpels of the
pistil are inserted. In the blackberry (Fig. 76), raspberry,
and Btriiwberry the »

receptacle is knob-

shaped, and the car- ^

pels are arranged on
the outside of the ^
knob, somewhat as ^

in the buttercup. ' .-M

Here again, however,

the calyx, corolla, and

stamens differ from

those of the buttercup

in seeming to arise

from a common base. ^ nS^\

* The differences be-

tween the rose, black- ^

berry, raspberry, and

Fig. 76. — blackberry, i, flowering branch (x i) ;

Strawberry are more 2, lon;gItu<'iIl.^l section of flower (xx); 3, fruit

, , , • . (X’O ; j, ili.i.>i .HU of flower,

marked when the

pistil has become a fruit. The fleshy part of the rose hip
is the urn-shaped receptacle which encloses the ripened

carpels. Tn the case
of the blackberry and
/ raspberry the receptacle
surrounded
compound fruit
' (Fig. 76, 3) of the several

flr J \ bodies like little plums

W ^’'cherries. Theeatabk

^ strawberry

H fruit (Fig. 144) is the

Fig. 77. — Cherry, i, •flowering branch (x§) ; SWOllen receptaclc, On

the outside of which

io6 AN INTRODUCTION TO NATURE-STUDY

are the little yellow nutlets derived from the carpels of the
flower.

In the cherry (Fig. 77), plum, and apricot the phtil con-
sists of only one carpel, which is enclosed in the urn-like

receptacle. After fer-
tilisation, the greater
part of the wall of the
‘ovary becomes fleshy,
and one of the two
ovules contained in it
becomes a seed. The
“stone” is formed from
the innermost part of
the ovary wall.

The apple (Fig. 74)
and pear (Fig. 78) have
their five carpels em-
bedded in the recep-

F,.;. .78.-Pear. . flowerine branch (x® ; and the rest of

2, longitudinal section of flowet ; 3, longitudinal floWCr Stands On

section of fruit ; 4, diagiam of flower.

this part. The eatable
portion of the fruit is the swollen receptacle. The hawthorn
has usually only two carpels, and in the fruit the part
derived from the receptacle becomes hard and horny. In
other respects it is very similar to the apple.

The ro.se family is widely distributed, especially in
temperate regions.

20. THE PARSLEY FAMILY.

I. The poison hemlock. — Examine this plant (Fig. 79) very
carefully, remembering that it is poisonous. Notice the general
habit of growth ; the characters of the sheathing, compound
leaves ; the hollow ribbed stem ; and also the arrangement of
the flowers, which is characteristic of theTamily. From the top

t;he parsley family

107

of a main flower-stalk several smaller stalks come off together,
like the ribs* of an umbrella. From the top of each of these
spring tl}e*stalklets which bear the small white flowers. Notice
the bracts at the points oi ori^n of the stalks. Examine the
flowers, and watch insects visiting them. Which insects are
most commonly found on the flowers ?

Compare the cow parsnip, the water hemlock, carrot, parsley,
parsnip, and celery, carefully noting the points of resemblance
and difference. •

The parsley family. — The plants of this family may be
recognised easily by the arrangement of the flowers. Several

stalks spring together from the to]) of the main flower stalk
and each of these again gives rise at its tip to a number of
smaller stalks, at the ends of which the small flowers are
borne (Figs. *79^ and 80). The flowers are fertilised by the
aid of insects, and as the nectar is on the surhice it is

io8 AN INTRODUCTION TO NAT VRlI sTUDY

accessible to small insects such as flies, beetles, etc. The
flowers are rendered more conspicuous by being placed close
together. The stems are usually hollow, and the loaves are
alternate, and’ generally cqmpoufid, with sheathing bases.
Many of the plants of this family arc very poisonous, and
su^i should be carefully distinguished and whenever possible
exterminated.

The poison hemlock (Fig. 79) varies, in height from two to
seven feet. It has a hollow stem which is spotted with purple
in the lower part, and when bruised the leaves give off a
smell like that of mice. Cattle are often poisoned by eating
the plant in hay, and children have been poisoned even by
blowing whistles made from the stem. 'Fhe water-hemlock
is extremely poisonous. It grows along the sides of pools.
The stem is hollow, and the leaflets of the compound leaves
are finely toothed, d'he root is a cluster of fleshy swellings,
and has unfortunately a rather pleasant taste. Other poison-
ous plants of the family are the water dropwort and the
fool's-paraley. Among the harmless and useful members of
the group are celery (when cultivated), carrot, parsnip, and
parsley.

21. THE PRIMROSE AND COWSLIP.

I. The primrose. — Examine the habit (Fig. 81) of the plant, its
underground stem, its spoon-shaped leaves arranged in a rosette
* — and the manner in which the flowers sjiring from the stem. In
the flower make out (('A the C(ilyx\ 5 -])()inted and with united
sepals; {b) the corolla^ consi.sting of 5 petals united below into a
tube. 1 ear down the corolla-tube to see (r) tlic 5 sia 7 ne?is
inserted on the corolla-tube. In some (“thrum-eyed”) flowers
the anthers are at the top of the tube ; in others (“ pin-eyed ”),
they are halfway down ; (^/) the consisting of stigma,

style, and ovary. In thrum eyed flowers the style is short and
the stigma is halfway down the corolla-tube : .-while in pin-eyed
flowers the style is long and the stigma is at the top of the

THE PRIMROSE AND COWSLIP

109

tube. Do yoif find both pin-eyed and thrum-eyed flowers on the
same playt,*or docs one plant begr only one kind.'^

2. Fertilisation — Cover ujS
a plant of each kind with
gauze, to keep insects from
the flowers, and notice
whether the covered floweis
ripen seeds like the others.

3, The cowslip.— Compare
the cowslip (Fig. 83), and
notice that the main stalk
gives off from the same point
several smijiller stalks, .each
of which bears a flower.

Observe that the cowslip
also has both pin-eyed and
thrum -eyed forms of flowers.

The primrose and cow-
slip. — In the primrose we
have flowers of a type dif-
fering from all those ]^revi-
oiisly considered in this chapter. Not only are the sepals
joined together to form a five-toothed calyx-tube, but the five
petals are also joined together to form a corolla-tube, and the
stamens are fixed on the corolla-tube. There are two kinds
of primroses, known to country children as pin-eyed and
thrum-eyed flowers respectively (Fig. 82). The two forms
grow on separate pfants. In a pin eyed primrose the style
is long, and the stigma — looking somewhat like^the head of a
pin— is at the top of the corolla-tube ; while the stamens are
half-way down. The thrum eyed primroses have their
stamens at the top, while the stigma of the pistil is half-way
down the tube’, ej^actly opposite the place where, in the pin-
eyed foriji, the stamens are inserted. This curious state of
things was a great puzzle to botanists until Darwin cleared

AN INTRODUCTION TO NATURE-STUDY

up the mystery. A bee, thrusting its probosci^i down a pin-
eyed primrose in search of the nectar at the bottom^ dusts it

Fku 82.- Chinese Primrose. long-styled (“ pin-eyed ”V flower ;
A”, short-styled (tliruni-eycd ”) flower ; G, stigma ; A, anthers.

with pollen about half-way down — just in the place which
will come in contact with the stigma when the animal
visits a thrum-eyed flower. And the pollen from the

Fig. 83 -Cowslip, (x^.)

thrum-eyed form ad-
heres to the part of the
bee which will presently
touch the stigma of a
long-styled flower. This
beautiful and simple
arrangement . makes it
practically certain that
each primrose shall be
fertilised by pollen from
the other form. In the
thrum-eyed form, how-
ever, it is possible for
pollen to fall upon the
stigma and produce self-
fertilisapoh.

It is obvious that
the cowslip (Fig. 83) is

THE DAISY AND ITS RELATIVES

III

closely related to the primrose. The difference lies chiefly
in the character of the flower-stalk. In the cowslip this is
long, and it bears at its top several stalklets, each of which
ends in a flower. As in the piimrose, cross-fertilisation is
secured by some flowers being pin eyed (long styled) ,,?«d
others thrum-eyed (short styled).

22. THE DAI^ AND ITS RELATIVES.

1. The daisy. — Take up several daisy plants (Fig. 84) entire,
and wash away the soil from the roots. Notice lunv the stems
— some of which are underground — are connected together.

Draw a leaf. What advantage is it to the plant to have leaves
of the shape noticed'? Cut vertically through the “head,” and
notice that what is usually called the “ flower” really consists of
a large number of small flowers.

The central or disc flowers are tubular. Which disc flowers
open first, those , near the middle or those nearer the edge of
the disc? Pick off a flower and notice the 5-toothed corolla.
Tear the corolla .down with a needle, and observe the tiny
stamens (5) fixed on the corolla-tube. The anthers are joined

112

AN INTRODUCTION TO NATURE-STUDY

together. Notice the divided stigma of the pistil. The white and
pink ray flowers have strap-shaped corollas. I'hey have no
stamens, but each has a pistil like that of a disc dowser. What
do you think is the object of the ray flowers being so con-
spicuous ? Why do they close over the disc at night ?
iwtice the large number of green bracts below the disc.

2. The dandelion.-- Compare the dandelion (Fig. 85). Notice
that all the flowers are strap-shaped, like the ray flowers of the

daisy. Pull one out, and
make out the strap-like
corolla, the five stamens
with joined anthers, and
the double stigma (Fig.
86, 2). Notici the tuft of
fine hairs below the corolla
and above the knob-like
ovary, 'rhe tuft of hairs
is the lop of the calyx-
tube.

When the flowers have
been fertilised, the yellow
corollas wither, and each
calyx-tube elongates until
it is al^out an inch long,

I the tuft of fine hairs being

Fig. 85. -Dandelion. (X].) still at the top (4). Iflow

a “clock,” and notice how
easily the fruits are detached from the disc and how slowly
they settle. What advantage is this to the plant ?

3. The thistle. — Compare the thistle (Fig. 87). The bracts
are very prickly. Is this an advantage? Arc the flowers
tubular or strap-shaped? Examine the fruits (“thistle down”)
and compare with those of dandelion.

The daisy. —What is generally called the “ flower of the
daisy (Fig. 84) really consists of a very Jarge number of
small separate flowers set close together on a flattened disc

TiHE DAISY FAMILY

”3

or receptacle. . The group of flowers is called a liead. On
the lower surface of the head are several green leaves, or
bracts, whicb protect the bud b^ifore it opens. The flowers
of a daisy-head are of two kinds. • The white or pink straps
set round the edge of the head are the corollas of the rnf
flowers. They have no stamens, but a pistil with a divided
stigma is present in each. The disc flowers are yellow and
tubular. The corolla ’

five s^araen^'^t^

■ I’he'flaiijelton “flmver” _ ' i ,

Fig. 86. — Dandelion, i, two heads and a leal
(Pig. 85) is. also really (x^); 2, a single flower (X 2); 3, fruit (xf);
11 • r 4, receptacle, with one fruit.

a head consisting of a

great many separate flowers. There are often between
two and three hundred of the.se little flowers present
in one head. Below the head are several green bracts,
and these protect the flowers both in the bud and at
night (p'ig. 86). The flowers of the dandelion are all of
one type. The corolla is strap-shaped (P'ig. 86, 2), and
of a beautiful yellow colour to attract insects. On the end
of the strap may be, seen five small teeth which indicate that
it really consists of five united petals. At the base of the

Fig. 86. — Dandelion, i, two heads and a leaf
( X ^) ; 2, a single flower ( X 2) ; 3, fruit ( X |^) ;
4, receptacle, with one fruit.

114

AN INTRODUCTION TO NATURE-STUDY

corolla is a tuft of fine hairs,
tube, and at the bottom of th

Fk;. 87. — Thistle, (x^.)

from the attacks of ani

which is the top of the calyx-
^ flower is a littleVhite knob —
the ovary. T'hc five stamens
are fixed on the inside of the
corolla tube. Their anthers
are united to form a tube
through which the upper part
of the style, and the forked
stigma protrude.

It will be noticed that a
dandelion flower is practically
like a ray flower of a daisy,
witli the addition of calyx and
stamens.

*The thistle {Fig. 87) is
another common member of
the family. Its bracts arc
prickly, and are a protection
The flowers ^(E'ig. 88) are all

tubular. 'Ehe common thistle distributes its fruit
by a plume of radiating fine hairs — the calyx.
The fruit is commonly known as “thistle down.’’

The Compositae, as plants of this family are
called, are found in all parts of the world. The-
family is the largest in the vegetable kingdom,
and many of the plants included in it are of con-
siderable importance.

Fir.. 88.—
Tubular flow-
er of Thistle
(magnified).

23. THE FOXGLOVE FAMILY.

I. The foxglove. — Examine a flowering plant of foxglove
(Fig. 89). Notice the general habit of growth. In the flower
make out the five-lobed calyx, the irregular corolla with five
petals joined to form a tube, the four stamens (two long and two
short) fixed on the corolla tube (Fig. 90),* and the form and
attachment of the pistil. Watch bees visiting the flower.

the' foxglove family

2. The speedwell. — Compare the speedwell (Fig 91), and
notice that ^the corolla is more nearly regular than is the case
with the fbxglovc, that it consisUjiof yi;//;- combined petals, and
that two stamens are fixed upon it. *

3 The musk — Compare the musk. Dissect a flower f'Jid
notice the forms and positions of the parts. Especially examine
the pistil with its two-lobed stigma. With a hair, carefully touch
one of the lobes of the stigma of a growing flower and watch
how the lobes dose. Do the lobes open again ? Put a little
pollen on, and w'atch
to see if this time the

kibes open apibn nfter ^ ‘

The foxglove •fam- U 'W'

ily.— In the primrose

and the disc-flowers \\ ^ -w |\

of the daisy are seen m -

dicotyledonous flow- Vil

ers with flve petals ^ f

fused to form a cor- .. ^ i.

olla tube, and with

five stamens inserted on the corolla. In the strap-shaped
flowers of the dandelion the corolla is irregular, but still
consists of five fused petals and bears the five stamens.

The foxglove (Fig. 89) and its relatives have also irregular
corollas of joined petals on which the stamens are fixed ;
but the' stamens a!-e usually only four in number, two being
Jong and two short as in Fig. 90, b. In the foxglove the

ii6 AN INTRODUCTION TO NATURE-STUDY

stamens ripen and shed their pollen before, the pistil of
the same flower is mature. This prevents selfTertilisation,

•but humble bees in passing
from one flower to another
convey the ripe pollen of
the younger flowers to the
stomas of flowers which
are ready for fertilisation.

The pretty blue speedwell
(Fig. 91) is closely related
to the foxglove, but its
corolla has only four lobes
instead of five, and some
41 times these seem of almost
equal size at the first glance.

Fig. 9o.-Fo.giove. flower corolla however, the

cut oi)en and spread out ; r, calyx and pistil;
fruit f section of fruit. ( X J.)

corolla is very plainly irregular.

The speedwell has only two
stamens, while mullein has five.

Calceolaria, musk, gloxinia, and
snapdragon — other members of
the family— are often cultivated
in gardens.

The flowers of the musk are
especially interesting, because
they show so well what is called
irritability, — the power which all
living things possess of acting
in a definite manner in re-
sponse to a definite irritation
or stimulus. We have already
seen good examples of plant-

Fig. 91. Speedwell (xi*)

THE LABIATES

117

irritability in the way a climbing stem winds itself round a
support. The stigma of the musk flower has two flaps. If
these are touched with a h^ir oc bristle they quickly close
together, but presently open again as if they had found out
that they had been tricked. When, however, a little polLiT
is put on the flaps they close finally, for their whole object
is accomplished. ^

Some of the plants in this family are poisonous, the
foxglove being especially so in all its parts.

24. THE LABIATES.

1. The deadnettle. — Examine a dcadnettle ^plant (Fig. 92)
Notice the habit of growth, and write down a description of the
shape and appearance
of the stern and leaves.

What is the shape of the
flower? How many se-
pals, petals, and stamens
has it? Do the Jtarnens
ripen first, or docs the
pistil? What insects do
you find visiting the
flower ? Try to find out
how they pollinate the
stigma.

2. Other labiates. — Com-

pare the sage (especially
in respect of its relation
to bees), rosemary, thyme,
marjoram, and mint, and
distinguish between their
various flowers, leaves, Fig. 92.— White Deadnettle. (xi)

and scents.

The labiates. --^The deadnettle is a type of an easily
recognisable family of plants The stem is square in section,

AN INTRODUCTION TO NAfURE-STUDY

ii8

and the leaves are arranged upon it in opposite pairs at right
angles to each other. The plants are hairy and have
distinctive odours. The (tron\a of thyme, mint, marjoram,
sage, etc., has led to the*})lants being used for flavouring
None of the labiates is poisonous.

The shape of the flower is very characteristic, and is
.specially adapted to the visits of l^j^^es. The flowers are so
modified that the lowest part of the corolla forms a platform
on which the bee may conveniently alight, while the upper

petals unite into an arched roof which })rotects the pistil
and stamens.

The mechanism of cross-pollination is [particularly well
shown in the ca.se of the sag-e (Kig. 93). The flower
contains four stamens, but two of these have lost their use,
and the others are modified in a strange manner. The
whole stamen has .somewhat the shape of a capital T, and at
each end of the cross-piece is a pollen box. Usually the
cross-piece (c, Fig. 93, 3) is not at right angles to the
filament, but is swung up —the junction acts as a hinge —
until it is nearly vertical (Fig. 93, 4). Thte pollen box y,
which is at the lower end of the cross-piece c when this
is vertical, contains hardly any pollen. The entrance to the

LIU' Ato SNOWDROP FAMILIES 119

honey tube is* thus guarded by two pillars, the filaments (/)
of the stanjens ; and the lower pollen box (s) of the cross-
piece of each stamen is directly*in front of the bee’s head as
it stands on the lower lip of the flower. When it pushes
forward its head to reach the nectar it comes in contact
with the lower pollen boxes, and the cross pieces swing
round on their hinges.^ bringing the U[)per pollen boxes
down with a smack on the bee’s back (Fig. 93, i), and
sprinkling it liberally with pollen dust. Having shed their
pollen the stamens shrivel up, and the pistil comes to
maturity. As the pistil ripens, the stigma arches over
(Fig. 93, 2^ so as to scrape along the back of any bee
visiting the flower for the nectar, and thus* to wipe oft the
pollen which has been brought from a younger flower.

25. THE LILY AND SNOWDROP FAMILIES.

1. The hyacinth. — Take up a plant (Fig. 94) entire and notice
the underground bulb with roots springing from its lower sur-
face, and the long narrow leaves. Is the venation of the leaves
parallel or net-like? Is the hyacinth a monocotyledon or a
dicotyledon ? See the bract at the base of each flowcr-stalklet.

Examine the flower. Its leaves cannot be distinguished into
calyx and corolla, but arc cpiite similar to each other in size,
shape, and colour. They are therefore called the perumth.
The perianth leaves are united to form a tube. Tear down the
tube to see the six stamens fixed on it. Are they all on the
same level? Examine the ])\slil and cut the ovary across to see
the ovules in the three joined carpels. Which is fixed at the
higher level, the perianth or the base of the pistil ?

2. Other plants of the lily family. — Examine also the white
lily, tulip, star of Bethlehem, and lily of the valley, and notice
.that in spite of. small differences they are all monocotyledons
(how do you know^this ?) and all have the perianth fixed below
the ovary.

120

AN INTRODUCTION TO NAfuRESTUDY

3. The snowdrop. — Compare and contrast ‘the snowdrop
(Fig. 95). Make out that it is a monocotyledon,^ but that its
perianth is inserted above theovar^. This is the gre'at point of
difiference from the lily family. Notice also how the stamens

fixed.

4. Other plants of the snowdrop family. — Examine the daffodil
(Figs. 55 and 96) and narcissus. Arising from the short perianth

tube of the daffodil is a longer one which is often mistaken for a
corolla ; it is called the corona. None of the flowers hitherto
described contains anything corresponding to a corona. The
corona in the narcissus is short. As in the snowdrop, the
perianth is fixed above the ovary. Observe how the stamens
are fixed, and notice the dry leaf beneath the flower.

The lily family. — Either the wild hyacinth (Fig. 94) or the^
cultivated single hyacinth may be taken* as a good repre-
sentative of this family. The first point which strikes the

THE LILY FAMILY

121

Student on examining the general “ habit ” of the plant is the
character^ of the long sheathing leaves. Their veins do not
form an obvious network, such* as is seen in the leaves of
dicotyledons, but run lengthwise and roughly parallel t^
each other in the manner characteristic of grasses and other
monocotyledons (p. 40). The leaves are narrow, and are not
divided into blade ancV stalk ; they and the flower stalk
spring from an
underground bulb
(p. 84) which con-
sists chiefly of the
swollen lea*f-bases
of a previous sea-
son. A separate
calyx and corolla
are not to be dis-
tinguished in the
flower ; the six
leavjes being All
alike in size, shape,
and colour. These
six leaves hence
receive a special

name and are ^ flower, cut down the middle. (x|.)

called the perianth. The perianth leaves are united into a
tube, on the inside of which the six stamens are arranged
in two series of three each. In the middle of the flower,
and fixed above the hmrtion of the perianth^ is the pistil,
which consists of three united carpels.

It will be noticed that the parts of the flower are in threes.
There are six united perianth leaves (three inner and three
outer), six stamens (also in two series), and three united
carpels. This is very common — though by no means
universal — in monocotyledons.

122

AN INTRODUCTION TO NATURE-STUDY

All the plants of the lily family — including, the tulips, the
true lilies, lily of the valley, asparagus, onion, etc. — agree in
being monocotyledons, and' in their flowers having a con-
spicuous perianth (for attracting insects) and six stamens,
aiftl in the ovary being above the insertion of the perianth.

The snowdrop family.— Plants of this family are very
similar to those of the lily family ; i^r fact in only one respect
can any sharp line of demarcation be drawn between the
two groups ; in the snowdrop and its relatives the other parts
of the flower stand upon ihe ovary (Pig. 96). d'he flowers of
some plants of the family, e.g. the daffodil, possess a tubular
outgrowth of the perianth, which is called a c®rona. It is
often mistaken for a corolla.

26. THE ARUM LILY.

I. The cuckoo-pint. —Examine the habit of the plant, and
then cut open the “ flower,” You will probably find a number
of small flies inside. Examine the central rod and make out the
stamens and pistils on it. Which ripen first?

The arum “lily,’' with its humble relalive the cuckoo-
pint (Fig. 97), merits special mention ; for, in the first
place, it is not a lily at all, and secondl)', it furnishes an
extremely interesting example of pistils coming to maturity
before anthers, which is rather rare.

What is generally called the “ flower ” of the cuckoo-pint,
or “ lords and ladies,” consists of a big curled leaf with a
purple rod sticking up in the middle. Near the bottom
of the rod, but hidden from sight by the lower part of the
leaf, the true flowers arise. The chamber containing them
is shut in by a series of stififish hairs which point down-
wards. Below the hairs the rod supports a series of
anthers and, near the bottom of the chamber, several pistils.
On cutting open the chamber one nearly ‘always finds a
number of small flies, covered with pollen, which they have
brought from another arum. The flies get in easily

THE CUCKOO-PINT

123

enough, but once in they are prisoners, for the down-pointing
hairs prevent them from getting out again. "J'he pistils near
the bottom of the rod ripen, and are fertilised by the pollen
the flies have brought. After a time the anthers above

Fig. gj.— A, Cuckoo-pini. (xP) In A’, the front of the leaf is cut
away to show the rod ((’)■ female (lowers; Af, male flowers;

J/*, undeveloped male flowcis.

ripen and shed their welcome pollen on the hungry captives.
Soon after this the hairs at the top of the chamber shrivel
up, and the flies, once more covered with pollen, are at
liberty to return* to the outer world and, untaught by
experience, to repeat the experiment on another flower.”

AN INTRODUCTION TO NAfURE-STUDY

EXERCISES ON CHAPTER VI. ,

I. Describe the arrangement of the' stamens in the wallflower, the
sage, and the primrose.

^***^'. Describe the pistil of the deadnettle, the primrose, and the
shepherd’s purse.

5. In whsit respects does the dower of ^Jie buttercup differ from that
of the wild rose ?

4. Explain the arrangement and form of the stamens in some flower
selected by yourself. Describe the structure and contents of the anther.

(1897)

5. Where is the pollen of a flower formed ? What is its use? (1898)

6. Name one or two plants which do not ripen seed* if insects are

excluded, and shovt why they do not. (*898)

7. Name two plants which would be in flower in each of the months

from March to August inclusive, and state in what localities they would
be found? (N.F.U.)

8. In what ways are insects attracted to visit flowers ? Give examples,

with ay, explanation and drawing in each case, of any special structure
which may be a means of attraction. (N.F. U.)

9. Name ten flowering plants which may be found, (a) in a shady
wood, (fi) in a meadow, in late spring.

10. Name any fresh specimens of flowers which usually could be
obtained growing wild in March, June, and October respectively.

(N.F.U.)

11. What wild flowers would you expect to find in early April in

your part of the country ? In what kinds of places w^ould you look for
them? (N.F.U.)

12. Name the parts of any flower you have examined w^hich are
concerned with the production of seed. (King’s Scholarship, 1904)

CHAPTER VII.

GRASSES.

27. THE EVERYDAY LIFE OF A GRASS.

I. General features. — Pull up a sod of couch grass or of
Yorkshire fog and clear away the earth as well as possible.
Notice the fibrous, creeping branches or stolons^ and the bunches
of fine roots. In summer the plant sends up also erect branches
called haulms^ which bear leaves and flowers. Examine the
shape of the leaves and notice their parallel venation.^which
indicates (p. 40) that the plant is a monocotyledon.

Observe how tihe leaves are borne on the haulms. Each leaf
arises at a knot (node) which is slightly swollen. The first part
of the leaf is a sheath which encloses the haulm up to perhaps
the next knot. Then the leaf-blade stands out from the haulm.
Turn back the blade slightly and notice at this point a little
strap, the Itgule (Fig. 98), on the upper surface of the leaf-
blade. Notice the variation in the size and shape of the ligules
of different kinds of grass.

Pull the haulm until it gives way, and draw the broken part
out of the leaf-sheaths. Chew the end, and notice the taste of
sugar. Cut across haulms of various ages. The young haulms
are solid ; the old ones are hollow except at the nodes, where
there is a horizontal shelf. Notice this also in a bamboo cane,
which is the haulm of a large tropical grass. In spring, mark
a young haulm, so that you can recognise it, and measure it day
by day. Note die measurements made on various days, and
also the date of opening of the flowers.

126

AN INTRODUCTION TO NATORE-STUDY

2. Different grasses.— Learn to recognise different grasses,
not only by the way in wliich the clusters of flowers are borne
on the haulms (Figs. ro2 to i lo) and by their colours, but also by
the general appearance of the f)lant when it is not flowering ;
^ size and shape of the leaves, the character of the ligules, the
manner of rooting, etc.

Again g;crminate grains of wheat, and especially notice the
single cotyledon, the leaves, and root:^(p. 21).

Importance of grasses. — It is impossible to over-estimate
the value to man of the various grasses From the earliest
times he has obtained his staple food from the grains of
such cereals as wheat, barley, oats, rice, and maize ; and his
flocks and herds^have grazed upon the nutritious herbage of
the plains. The numberless applications of such large
tropical grasses as the bamboo and the sugar-cane are also
well known. Sugar occurs very generally in grasses. It can
easily be recognised even in ordinary meadow-grass by
pulling out the upright ^‘stem’^ from the sheathing leaves,
and chewing the tender end. ^

The general characters of grasses. — In this country,
grasses are usually herbs not more ihafi three or four feet
high. They have abundant leaves, which are long, narrow,
and pointed at the end ; tlu'y have parallel veins like the
leaves of most other monocotyledons. The roots,- too, are of
the usual monocotyledonous type — springing in bunches
from the base of the stem, not branching from a main tap-
root. Most grasses .sj)read by prostrate creeping branches
or stolons (p. 83), which spring from the axils of leaves
and then run along beneath the soil. At some little
distance from the parent shoot, the stolon forms roots below
and a new shoot above. Other stolons arise in the axils of
the leaves of the new shoots, and so the process is repeated.
In this way such grasses become thoroughly established in
the soil, and — if they are of the undesirable species which

CHARACTERS OF GRASSES

127

are classed as weeds ” — cause much trouble. This habit

of growth is, hbwever, useful in binding together the sand
and earth . df embankments, et|^., into a compact mass.
The new shoots of stolon-bearing ^grasses are of two kinds.
Throughout the greater part of the year they consist of*
tufts of leaves ; but, in the spring and summer, there are
also produced erect branches — commonly known as stems,
but better called haulms — ^Vhich bear leaves
in the “alternate” manner, ddie point at
which a leaf springs from the haulm is
called a knot or node ; it is usually swollen.

'The distance between two knots is, of
course, an internode. Extra roots are often
given off from the lower nodes of the
haulm.

The lowest part of the leaf is a cylin-
drical, and generally split, sheath (Fig. 98),
which closely embraces the haulm for some
distance — often for the length of an inter-
node. The sheath protects and supports
the soft, growing internode, inside it. At
the top of the sheath is the blade of the
leaf, which stands out from the haulm. At
the junction, of the blade and sheath, on
the upper surface of the leaf, is a little membranous out-
growth called a ligule (Fig. 98, /). It often varies greatly
in size and shape in different species of grasses, and is
a valuable means of distinguishing between them. Its use
is not certainly known. Tlie student should examine the
ligule of every grass he studies.

The haulm, or flowering branch, is for some time short
and solid, and its nodes are so close together that the
sheath of a lower, leaf may overlap several upper leaves.
The haulm is thus protected from the rough weather of the

Fig. 98.- Part of a
nr.i.ss Stem and Le.af.
h, haulm , s, part of
leaf-blade ; /, ligule ;
7 >, leaf-sheath ; X.’,

node-like swelling at
the base of the leaf-
sheath (x^.).

128

AN INTRODUCTION TO NAXURE-STUDY

early spring. In the meantime, the flow^s have been
developing at its upper end. When they arv^ almost ready
to open, the haulm begins to grow very rapidly > its inter-
nodes elongate so quickly, (hat the internal tissues are torn
^d the haulm becomes a hollow straw, except at the nodes,
wliere there are horizontal shelves. The haulm hardens
and stiffens as it grows, so that, when the spikelets of
flowers at its upper end open, they are carried high above
the leaves on a slender but very strong rod, which bends
and dances in the wind, and allows the pollen to be
detached and blown to the stigmas of other flowers.

28. THU REPRODUCTION OF A GRASS.

I. The arrangement of the spikelets. — Gather ears (flowering
haulms) of several different kinds of grasses and notice the
arrangement of the flowers. In the
oat (Fig. 99), the meadow grasses
(Fig. 103), fescues (Fig. 102), and others,
the nodding oval boVlies, called spike-
lets, are borne on delicate stalks which
spread outwards from the haulm. In
the foxtails (Figs. 104 and 105), timothy
(Fig. 106), and sweet vernal grass
(Fig. no) the spikelets are on short
stalks, which can, however, be seen
on bending the ear sharply on itself.
In wheat, barley, couch grass, rye,
and rye grasses (Fig. 109) the spikelets
are devoid of stalks and are set close
along the haulm. Be quite sure you
understa?id what is meant by a spike let.
39 spikelets are shown in Fig. 99.

2. The arrangement and structure
of the flowers. — Ta^e an open spike-
let from the ear of a grass (^^. oat) which has large flowers.

REPRODUCTION OF A GRASS Ug

and examine it. At the bottom are two boat-shaped leaves —
really bracts— called glumes. Remove them carefully. Above
them will he found two or more flowers, each flower en-
closed in two other leaves. The^outer of these two leaves is
called the outer pale \ the inner is the inner pale. From the
middle of the back of the outer pale of the oat springs a brisU^
called an awn. Remove the outer pale and make out the three
anthers on long filaments, and the ovary with two branching
feathery stigmas and shoi*t styles. Fig. loo is a diagram of a
spikelet, which makes clear the relation of the glumes, pales,
and flowers. Fig. loi, A., is a spikelet of meadow fescue. Its
outer pales differ from those of the oat in not bearing awns.
Otherwise it is very similar. Fig. loi, i/, shows the appearance
(magnified) of a flower of meadow fescue from which the outer
pale has been removed. The two little scale?^ seen in front of
the ovary possibly represent a perianth. Be careful not to con-
fuse the terms ear, spikelet, and flower. The ear consists of a
• number of spikelets, and each spikelet consists of glumes and
one or more flowers.

Similarly dissect spikelets and flowers of other grasses,
making notes of the lengths of the stalks of the spikelets, and
the presence (and* lengths) or absence of awns.

3. The use of the awns. — Try to find out the use of the awns.
Are they generally rough or smooth? Have you ever seen
grass “ seeds ” sticking in the wool of sheep ? What kept them
attached ?

4. Qrain.~Examme several kinds of grass “seeds” and
make out that they not only consist of the entire ripened ovary
and are therefore friats., but that usually the pales also remain
attached to them.

5. The embryo and endosperm. — Again cut through soaked
grains of maize and wheat, and make out the embryo and
endosperm (p. 19).

Grass flowers. — Grasses are true flowering plants ; but
because they depend on the wind for the transference of
pollen to the stigmas, they do not pander to the ta'ste of bees
and butterflies by secreting nectar, and hence have no need

N.S. I

130

AN INTRODUCTION TO NAi;URE-STUDY

to display those advertisement placards which we call
petals. For this reason their flowers are" not generally
recognised as such. It requires a little care to ,make out
the parts of the flower apfi to understand the manner in
^hich the flowers are arranged among themselves.

The whole group of flowers borne by any one haulm is
generally called the ear or panicle. The ear in its turn
consists of several bodies called spfkelets. The appearance
of the ear varies greatly in different
grasses (Figs. 102 to no) according as the
stalks of the spikelets are long and
spread outwards from the haulm, as
in the meadow-grasses (Fig*. 103), oats
(Figs. 99 and 108), fescues (Fig. 102),
and others; short, as in the foxtails
(Figs. 104 and 105), timothy (Fig. 106),
and sweet vernal grass (Fig. no); or
absent altogether, as in the wheat, barley,
rye, rye grasses (Fig. 109), and couch
grass.

A single spikelet of a grass is shown
diagrammatically in Fig 100. At the
bottom are two boat-shaped bracts called
grlumes (^, g), which almost or entirely cover the spikelet
before it opens. When the glumes have been removed a
few flowers remain. Each one is protected by two leaves
called pales : outer (/j) and inner (Z^) respectively. The
flower {B)j as a rule, has three stame?is, the anthers being
borne on long filaments and dangling out to the wind
(Fig. loi), and a pistil with two branching feathery stigmas.
In many grasses the outer pale bears a bristle called an
awn, well seen in ‘‘bearded” wheat, barley, and upright
brome grass.

Fig. 10 1 ^ At represents a single spikelet of meadow fescue,

Fig. ioo —Diagram of
a Grass Spikelet. the
glumes ; and A>, the
outer and inner pales ;
Z», flower.

REPRC5DUCT10N OF A GRASS 131

with two operl flowers. The outer pales of this grass are
not awned. Fig. 1 0 1 , B, shows a single flower of the same grass
from which the outer pale has.^ been removed. The two
little scales seen in front of the oWy (and at e in Fig. loo)
possibly represent all that is left of a perianth (p. 121). ^

Fertilisation. — By the time the flowers have opened, the
haulm has usually groy^n so tall
that they are lifted well above
the leaves. The stamens hang
their anthers loosely out to the
wind, and, as the slender haulm
sways in tjie breeze, the pollen
is readily detached and carried
to other flowers, perhaps miles
away.

It is in order to catch the wind-
borne pollen-grains that the stig-
mas of grasses are branched and
feathery. A gre^at waste of pollen
is obviously entailed by this method.

But on the other hand it must be
remembered that insect-pollinated f,g. loi.-Meadow Fescue,
flowers have to pay for their i?o\.e?s(x:l);t\flrrrm
privileges by storing nectar in cun-
ningly hidden pockets, and by
advertisement-expenses, all of which the grasses avoid.

The ovule is fertilised in the usual way, by a pollen tube
growing down the style from a grain on the stigma. As a
result of fertilisation the ovary becomes a fruit containing
one seed which fills it In many cases (c.^. barley and
oats) the pales still remain in position and adhere to the
fruit. When the awn is present it may play an important
part in distributing the “ seeds ” by clinging to the hides of
animals, etc. Sometimes the awn is of use in fixing the

132 AN INTRODUCIION TO NATURE-STUDY

grain in position on the ground until the seed has
germinated.

The structure of a grass/-, seed has already (p. '^19) been
studied in the wheat and* maize. The developing embryo
(jp. 21) lives upon a store of food called the endosperm
(Fig. 16) until its roots and leaves are sufficiently advanced
to make food for themselves.

29. SOME COMMON ORASSES.

1. The fescues. — Gather plants of meadow fescue^ and examine
the habit of growth (in tufts), the broad leaves, and the nodding
panicles and the flowers. Also examine the “ seeds.”

Compare sheep s fescue (Fig. 102), and notice the very fine
leaves. The outer pales are awned.

2. The meadow grasses. — Examine the various species of
meadow grass (Fig. 103). They can be distinguished from
each other by the characters of the ligules. Notice the tree-like
habits the panicles and compare them with the fescues. The
meadow grasses never bear awns. Notice the woolly “webs”
at the bases of the “ seeds.”

3. The foxtails.— In meadow foxtail (Fig. 104) notice the
prostrate stolons and large succulent leaves. Does the grass
grow in tufts Why not ? What is the earliest date, on which
you have seen it in flower ? Double the ear on itself to see the
short stalks of the spikelets. How many flowers are there in
each spikelet ? Notice the silky awns of the flowers.

Compare the slender foxtail {F\g. 105), which is a troublesome
weed.

4. Timothy. — Compare the leaves and flowers of timothy or
“meadow catstail” (Fig. 106) with the meadow foxtail. The
ear is green and rough, and the flowers are awnless. What is
the date of flowering ?

5. Yorkshire fog. — Notice the woolly covering of this weed
(Fig. 107). This covering and its bitter flavour make it dis-
tasteful to cattle. Observe the “ kneed ” awn of the flower.
Pig up and shake off the earth from a sod to see the stolons.

SOl^E COMMON GRASSES

133

6. Wild oat ’(Fig. 108). Examine the large spikelets and

make out the long twisted awn of the flower. Compare this
weed with the cultivated oat 99) and with the yellow oat
grass, *

7. The perennial rye grass.— Notice that the ear is flattened^
and that the spikelets are without stalks and have only one

Fig. 103.— Smooth-stalked Mea-
dow Grass. ( X

glume. The leaf is glossy and has a prominent midrib and a
flattened sheath.

8. Sweet-scented vernal grrass. — Notice the tufted habit of
growth and the characters of the leaves. Chew the stalk and
notice the sweet odour of new-mown hay. What is the date of
flowering ? Make out that the flower has two stamens only.

9. Rushes and sedges. — Rushes and sedges are sometimes
mistaken for grasses. Examine the stems, the flowers, and the
leaves (look for ligules), and tabulate as many differences from
the true grasses as possible.

134

AN INTROOTCTION TO NATVjRE-STUDY

The student should learn to recognise ®the common
grasses, and to distinguish the useful species frouj the weeds.
When the grasses are in flor^er there is not much" difficulty
in doing this, but the habft of growth — the characters of the
feaves and roots, and of the stolons of the perennial species
— should also be noticed carefully, as during the greater
part of the year these alone can be ^depended upon.

The fescues fall into two groups according as their leaves
are broad or narrow. The meadow fescue is a good example
of the former group. It is found in meadows and pastures
and has long broad leaves. Sheep’s fescue (Fig. 102) is a
good example of the second group of fescues. It has very
fine — almost bristle-shaped — leaves, Like^ the meadow
fescue it grows in tufts ; it inhabits high lands and downs,
especially in limestone districts. The nodding spikelets are

SOME COMMON GRASSES

135

borne on fairly long stalks, and the panicles are somewhat
like those of the meadow grasses (Fig. 103). The flowers of
sheep’s fescue, however, bear sh^rt awns.

The meadow grasses much resemble the fescues ir]^
general appearance, but the panicles (Fig. 103) are rather
more tree like — the stalks of the spikelets spreading more
horizontally — and the flowers are never awned. The
various species can be dis-
tinguished by their ligules ;
for example, the ligule of
the smooth-stalked meadow
grass (Fig. *103) is blunt,
while that of the rough-
stalked species is long and
pointed. The annual mea-
dow grass is a weed to be
found almost everywhere.

The foxtails are easily -
recognised by the tail-like
appearance of the ears
(Figs. 104 and 105). 'JTe
meadow foxtail (Fig. 104) is
a valuable grass with broad,
long, and succulent leaves.

It spreads by means of
prostrate stolons. The spikelets have short stalks, as can
be seen on bending the ear on itself, and each spikelet
contains only one flower. The silky awns give the ear a
silvery grey colour. The grass flowers in early spring. The
slender foxtail (Jog. 105) is a most injurious weed of corn-
fields. It can be distinguished from the meadow foxtail
by its less vigorous appearance, by the thinner; and more
pointed ear, and* by the black patches on the ear. It is
often called “ black bent.”

Fig. 106. — Timothy Grass, (xj.)

,136 AN INTRODUCTION TO NATURE-STUDY

Timothy grass or “meadow catstail” (Fig. io6) has a
general resemblance to meadow foxtail, but its ^ ears are
rough to the touch and giffeen in colour. It also flowers
guch later in the year (July) and its pales are awnless ; the
two grasses are therefore easily distinguished. Timothy
grows abundantly in clay soils, forming fairly close tufts.

Yorksliire fog (Fig. 107) is a rank weed which is dis-
tasteful to cattle, partly because it is covered with hairs and
is difficult to wet, and partly because it has a bitter flavour.
It is pale in colour and soft. It spreads rapidly by means
of creeping stolons.

Oat grasses are of several species ; one is /cultivated as a
cereal, others are valued as forage for cSittle, while others
still are troublesome weeds. The wild oat (Fig. 108) is a

590ME COMMON GRASSES

137

common weed in cornfields. It is an annual, from two or
three feet high, with large spikelets forming a loose panicle,
the flowers having awns twice asMong as the spikelets. The
cultivated oat is supposed to be a variety of the wild oat,
The panicle of the yellow oat grass is oblong, and has erect
spikelets.

Fig. 109,-- Perennial Rye Grass. (X^.) Fig. no. — Sweet-scented Vernal

Grass. (X^.)

The perennial rye grass (Fig. ,109) is very easily recog-
nised by its flattened ears of alternate, stalkless spikelets.
Each spikelet has only one glume. The leaves are dark-
green and glossy, and the leaf-sheaths are flattened instead
of being round, as is the case with most grasses. This is
one of the most valuable of forage grasses.

Sweet-scented Vernal grass (Fig. no) does not occur
very abundantly in meadows and pastures, but the fragrance

138

AN INTRODUCTION TO NATURK-STUDY

of new-mown hay is almost wholly attributed to it. The
odour can be distinctly perceived when a stalk of the grass
is chewed. The leaves somewhat hairy and are broad
^nd flat. The spikelets are borne on short stalks. The
flowers open early and are remarkable in possessing only
two stamens instead of three.

Eushestand sedges are mono-
cotyledonous plants which are often
erroneously called grasses. The
stems of rushes are vivid green,
round, and pointed, and contain a
distinct pith. The flowers (Fig.
in) are never in spikelets; they
contain six stamens, and the pistil
has three long stigmas. The sedges,
like grasses, have narrow, pointed
leaves, but the ligules are either
very small or absent, and the
leaf-sheaths are mot split. The
flowers are often in spikelets with
glumes, as are grass flowers. The
stems of sedges are solid and tri-
angular.

The flowers of rushes in many
respects resemble those of the
lily family. Indeed it is supposed that the ancestors,
not only of the lily family, but also (along a different
line) of the grasses and sedges, were primitive and now
extinct rushes. The lilies have developed the rush

perianth more and more as they have increasingly depended

on insects for pollination ; while in the grasses and sedges
the perianth has gradually dwindled because these plants
found that wind-pollination was sufficient for their needs.

flowering part of stem ; single
flower (/^) and pistil (6') more
highly magnified.

EXERCISES

>39

„ EXERCISES ON CHAPTER VII.

1. What grasses are grown as corX, in your pari of the country?
How can you recognise the grasses {a) before flowering, {b) in the ear,^
(c) by the straw ?

2. What forage grasses are most cultivated in your part of the
country ? Make a list of the earliest dates on which you have seen each
in flower.

3. Examine grains of wheat, barley, oats, and rye, as harvested. In
which of these are the pales present ? What is the “ beard ” of barley ?

4. Make a collection of “seeds” of various grasses, and write down
the characters by which they may be distinguished from each other.

5. What artf the commonest weeds you have seen in corn fields ? Do
the corn ahd the weeds flower at the same time or ni)t ? Is the time of
flowering an advantage [a] to the weeds, (b) to the farmer?

6. In what important respects do wind-fertilized flowers differ from

insect-fertilized flowers ? Give examples of each. (1898)

CHAPTER VIII.

COMMON FOREST TREES.

30. THE OAK FAMILY. ‘

I. The oak.— ((jz) Habits /?/ Examine an oak tree
growing in an exposed situation. What is its approximate
height t Estimate the diameter of the trunk at {d) the ground
level, {b) at heights of i, 2, 3, 4, etc., feet. At what height do the
principal ])oughs come off? About what angle do the boughs
mak^ with the trunk ? Are they straight, evenly curved, or
zig-zag ? Contrast in these respects an oak growing in a planta-
tion. Try to account for the differences observed.

{U) The bark . — Examine the barks in oaks of various ages.
Do the ridges and furrows caused by the splitting of the bark
form any definite pattern, or are they arranged anyhow ? Find
a piece which shows the pattern well, and make a drajving of it.

{c) Method of branching . — Carefully observe the tree from a
distance, and notice how the great boughs spring from the
trunk, and in their turn give rise to smaller and smaller branches.
Notice the shape of a tuft of the smallest twigs against the sky ;
then close your eyes and try to recall the picture. A still better
way is to make a careful drawing of the tree, not attempting to put
in details, but paying special attention to the ti'unk and main
branches, and to the general massing of the twigs. What is
the general ^‘^xpression ” of the tree ? Would you call it,
graceful, formal, sturdy, delicate, stiff, or sombre ? The method
of branching is best seen in the winter or spring, when the tree
is leafless.

THE OAK FAMILY

141

Examine a twig in winter or spring, and notice the position of

the buds. Round the tip there may be three or more crowded
buds. The one at the tip general!;^ dies, and those just behind

grow out into lateral branches. Ca.n you see any trace of this
having been the case with the big boughs ? On a twig make out'
— from the marks on the outside — the growth of last year, two,
three, and four years ago. Cut these lengths across with a
sharp knife, and count the jrings of wood.

(d) The leaves, — Watch a marked twig from spring to summer,
and notice how short are the new shoots which come from the
buds, and consequently how close together the new leaves are.
Does this account for the crown of foliage on the tree being
so dense? Make a drawing of an oak leaf. At what time of
the year do 0) the leaf-buds open, (ii) the leaves fall h orn the
tree ? In winter, try to find an oak which hfhs not shed its
leaves ; is it a young tree or an old one ?

{e) The Jiowers, — In May notice (i) the hanging catkins,
each of which is a bunch of male Jlowcrs containing stamens,
but no pistil ; (ii) the groups of small female flowers which
arise in the axils of two or three of the upper fr’mge '
leaves ; each contains a pistil, but no stamens. Notice the
cup of scaly bracts, which surrounds the lower part of a female
flower. Does the tree flower before or after the leaf buds have
expanded ?

(/) The fruit. — Trace the development of the acorn from the
female flower, and the change of the covering of scales into the
woody cup. Tf possible, compare for some years the yield of
acorns by a selected old oak. Germinate an acorn.

(^) Associated animals. — Make as full a list as possible of the
animals which you have seen obtaining food or shelter from the
oak. What was each doing when you saw it ? Look for galls
— the so-called “oak apples’^ — and cut them open to see the
insect inside. Also examine the other kinds of galls found on
the leaves and catkins.

[Make similar observations, sketches, and notes of other
forest-trees, in addition to the special observations mentioned
below, and learn to ^recognise their “expressions,” methods of
branching, bark, leaves, flowers, and fruit.]

142

AN INTRODUCTION TO NAtURE-STUDY

' 2. The beech. — Notice the smooth, olive-grey* bark, and the
“ fluted column ” appearance of the base of the trunk of many
beeches ; the long, wavy bojjghs ; the brown, sharp deaf-buds ;
the smooth, silky-fringed leaves ; the scarcity, or absence, of
•vegetation beneath tlie tree ; the hanging, globular catkins of
male flowers ; the pairs of female flowers, surrounded by prickly
scales. Make notes of the dates of flowering and opening of the
leaf-buds. Trees may be considered in flower when the stamens
can be seen. Trace the development of the fruit or “mast.”
Each pair of flowers gives rise to two three-sided nuts, enclosed
in a woody cup or husk. It is covered with hard bristles, and
splits into four parts when ripe.

Compare the sweet chestnut.

3. The birch. — Observe the graceful appearance* of the tree ;
the slender trunic, with its bark streaked with brown, yellow, and
silver ; the purple-brown colour and wirincss of the young
twigs ; the shape and size of the dark green leaves, and the
cylindrical, many-flowered catkins. The male catkins appear
in the autumn, the smaller female catkins in the following
sprriTg. Examine the two kinds of flowers. Find an old birch-
cone and break it open to see the winged fpiits. What is the
use of the wings ?

4. The hazel and alder. — In what situations do these trees
grow? Compare them with the birch. Notice that in both
hazel and alder the male flowers are in long, dangling catkins,
'fhe groups of female flowers of the ha/el look almost like leaf-
buds, but can be recognised by the spreading red stigmas.
The female flowers of the alder form distinct cones. Is the
flowering part of the twig of this year’s or last year’s growth ?
Look in the autumn for the cones and catkins wltich will expand
next spring. Trace the development of the fruit.

The oak. — The student cannot better commence the
study of forest trees than by selecting one as a type, and
making himself thoroughly familiar with its Jife-history, and
with its appearance at all times of the year. Other trees
should then be compared and contrasted point by point,

THE OAK

143

with this and with each other, d'he oak answers admirably
as such a cential type. It is perhaps the best-known of all
British forest trees, not only from its wide distribution, but
also from its historical and legenc^ary associations.

The oak (Fig. 112) flourishes in exposed and sunny situa-
tions, especially where the soil is well drained. It can be
recognised by the zig-zag and wide-spreading boughs, which
often spring from the tfunk almost horizontally. A very

I' lG. 1 12. — J lie- vjak.

Strong form of trunk is plainly necessary to support such
branches, and in an old solitary oak it may often be seen that
the bole is very thick at the ground line, and then rapidly
narrows, until at a height about equal to the base-diameter
it may be only half or one-third the thickness. Above this
point it is practically cylindrical up to the origin of the
boughs, where it is swollen. An oak growing in a wood, or
plantation, is of very different form. Its trunk is tall and
straight, and the larger boughs are not given off until near

?44

AN INTRODUCTION TO NATURE-STUDY

the top. To secure the necessary light, thjS tree used its
energy in growing in length, and in keeping pace with its
neighbours rather than in spreading laterally.’ .In such a
crowded oak the lateral b^ds generally remain undeveloped,
while the end of the shoot pushes onwards and upwards to
the light. The opposite is the
case when there is plenty of room
and light on all sides. Then it
is usually the terminal bud which
dies, while the lateral buds grow
out into branches, fornling the
“ knee-joints ” which were once
so greatly valued for'shipbuilding.

The bark of the oak is very
rugged, with ridges and furrows
running almost vertically.

The young shoots which are
formed when the buds expand
in spring are short, and the leaves
are set closely together. As a
result, the oak’s foliage is charac-
teristically dense and thick. The
leaves are very distinctive ; their
general shape is oyal, and the
margin is deeply and irregukirly lobed (Fig. 113).

If in early spring we go out in the woods and fix on an
old oak tree (the oak hardly ever flowers before it is 50 years
old), we shall probably see the flowers on some of the young
twigs. The female floivers — one to five on each flower-stalk
— are near the end of the twig, while the male flowers arise
lower down. The female flowers are destitute of stamens,
each consisting practically of a single pistil, partially enclosed
in two envelopes, the lower of which ultimately becomes the
familial; cup ” of the acorn. The stigma has three spread-

Fu;. 113. — The Oak; leaves,
flowers and fruit. flowering

blanch (x |) ; B, a male flower (mag-
nified) ; C, stamens (magnified) ;

a female flower (magnified) ;
E, acorns ; E', cup of acorn ;

6 ; //, seed.

145

ThIE OAK FAMILY

ing lobes for reijeiving pollen. The male sialks or catkins,
hang down frpm the lower part of the twig, and every stalk
bears about a dozen flowers. Th^ male flowers have each
from 5 to 1 2 stamens, but they have no pistil. The stamens

Fig. 114. -The Beech.

produce pollen in the usual way, and when they burst, the
wind blows the loose pollen from the stamens and scatters
it in the air. Some of the pollen dust is almost certain to
be wafted to the stigmas of the female flowers, and the pollen
grains put out tubes, and in due course fertilise the ovules.
N.S. K

146

AN INTRODUCTION TO NifrURE-STUDV

Most of our forest trees resemble the oak in being
pollinated by the aid of the wind. It is evident that for the
process to be successful )^ie trees must flower early in the
spring, before the foliage has become so thick as to be in the
way of the pollen and prevent it from reaching the stigmas of
the female flowers. It is also important that the j)ollen may
be easily detached, and it is for t^iis purpose that the male

Fig. 115.— The Ueech. 1, flowering; brnnch (x^); :i male flower
(X4) ; 3, a female flower ( ut thiouj^h lon^otiulmally (x 0 , 4, .cross section
of ovary ; 5, cup and friiitb (x'i); b, fruit.

flowers of the oak and similar trees hang down in the
familiar catkin fashion.

After fertilisation the female flower changes into an acorn
(Fig. 1 1 3, jE), a nut enclo.sed in a cup. The nut contains a
single large seed, which on germination grows up into a new
oak.

Galls of various kinds are to be foun(;l on most oaks
These are excrescences caused by certain insects having laid
their eggs in the soft tissues beneath the surface. More than

Tim BEECH

147

fifty species of Jnsccts obtain their food from the oak. Some
of these wiU be referred to in a later chapter.

The beech. — The beech (Tig. *^4) is easily recognised by
the olive-grey, smooth bark, and by the shape of the base of

Fig. jio 7'bc Birch.

the trunk, which usually has the appearance of being formed
by the union of several separate columns. When well
grown the tree is lofty, and bears a wide- spreading crown of
branches which^ when clothed with leaves in summer, casts
a dense shade. The ground beneath the tree is generally
destitute of other vegetation. The winter-buds are long and

148

AN , INTRODUCTION TO NA+URE-STUDY

pointed ; they expand in May, the new Jihoots at first
drooping, but straightening out in a fortnight pr so. The
leaves (Fig. 115) are broa^thin, and glossy, and are fringed
with fine, silky hairs. Young beeches, like young oaks,
often retain their leaves through the winter.

The tree is in flower by the time the foliage has fully

developed. The male flowers

Fig. 117. — The Birch ; leaves, flowers
and fruit, i, branch with male (/>) and
female (a) catkins (X^); 2, bract with
three male flowers ( X 2) ; 3, bract with
three female flowers (X4); 4, ripe cone
(X§); 5, fiuit (X^).

are .borne in small, rounded
catkins Fig. 115). The
female flowers (3, Fig. 115)
are in pairs. Each pair is
surrounded by prickly scales,
and gives rise iifter fertilisa-
tion to two three-sided and
pointed nuts enclosed in a
woody cup or husk. The
husk is covered with hard,
blunt prickles, and when ripe
splits into four parts.

Beeches .do not harbour
many insects, but squirrels
frequent them for the sake
of the nuts. The prickly
husks protect the fruit from
being eaten before it is ripe.

The Spanish, or sweet chest-
nut is allied to the oak and

beech. It has long, narrow leaves ; it flowers in July. Its
fruit is enclosed in a prickly husk, which splits into four
when the nuts are ripe in October.

The birch. — The birch (Fig. 1 16) is a slender, graceful tree,
with bark streaked with brown, yellow, and silvery patches.
Its leaves (Fig. 117) are rather small, and thpir glossy, dark-
green colour contrasts pleasantly with thfe brownish-purple
of the young twigs. Both male and female flowers are

THE HAZEL AND ALDER

149

arranged in catkins (Fig. 117). The male flowers appear in
autumn, but. do not open until spring, when the newly-formed
female flowers are ready. The f'^ale catkins (<7, ¥\g. 117)
are much smaller than the male (/f).

The hazel and alder develop their flowers in the year
preceding their opening. The female flowers of the hazel

Fig. h8.— The Kazel ; leaf, flowers Fig. iig.— The Alder; leaf, flowers
and fruit, i, 4 flowering branch (X§); and fruit, t, Branch with male catkins
2, a male flower ( X 2) ; 3, a stamen (a) and female cones (/^) ( X §) ; 2, male
(X4); 4, a female flower cut through flowers (xa'^); 3, female cone; 4, two
longitudinally; 5, fruit with cup (x^); female rtoweis ; 5, npc cone ( x §) ; 6, a
6 , fruit without cup ; a foliage leaf. fruit ( X i).

(Fig. I [8) look somewhat like buds, but may be distinguished
by the red stigmas. The fruit is a nut, enclosed by a sheath
of soft bracts. The seeds are largely dispersed by squirrels.
The alder grows on the banks of streams ; its female flowers
(Fig 1 19, are arranged in short catkins, which may be
called cones. The ripe cone (5, Fig. 1 19) contains two nuts
at the base of each* scale. The fruits fall into the stream, and
float ^way, perhaps to germinate at a considerable distance.

150 AN INTRODUCTION TO NATURE-STUDY

31. THE WILLOWY AND THE POPLAR.

I. The willow. — About the third week in March, examine
willow trees, and notice the soft, round, silky bodies which
spring alternately on the young twigs. On some trees these are
broad and yellow ; they are catJdns (Fig. 120). Pick off a
flower and see the stamens (generally two stamens to each
flower) inserted on a small silky bract
(Fig. 12 1, />). With a lens look for the honey
cup at the bottom of the bract.

On other trees notice the long, narrow,
silvery female catkins. Pick off flower to see
* the single pistil with the forked style, also on
a small, honeyed bract, llave you ever seen
bees visiting the flowers? Are the catkins as
cons])icuous when the trees are in leaf? Is it
an advantage to the trees to flower before the
leaves come out ? In J une, examine the ripened
female catkins Pull out a tuft of the hairy
seeds and dry it in th(‘ sun, noticing how they
form a fluffy mass. Plow the mass of seeds.
How do you think the seeds arc disjiersed ?

2. The poplar. — Find male and female pop-
lars and examine their flowers. Are the female

Ftfj. i2o.-Twif; flowers pollinated by insects or by the wind?
with^atkiri^(xT) self-fertilisatioii ever possible with willows
and poplars ? Wh) not ? Which appear first,
the flowers, or the leaves of poplars ? Why ?

Examine the leaves of the Fhiglish pojilar. Why do they turn
over so easily, even with a very slight breeze ? Arc both sides
of the leaf of the same colour ?

Compare the Lombardy poplar with the English poplar.

The willow. — Many species of willow ara known, but the
sallow willow — called the sa«ugli tree in Scdtland- -is common
in coppices and hedges. ]|t has purplish brown branches,

THE Willow and toplar

15 *

and large, broad, downy leaves. In the willow the male
and female flowers are produced on different trees, so that
self'fertilisa'tion is obviously impo.^sible. The flowers of the
male willow form broad yellow cmkins which cling closely
to the twig (Fig. 121). They are
often called ^\golden palms.” liach
flower consists of two stamens, borne
on a silky scale which has a tiny
honey cup at the base. The female
flowers form long, narrow, and sil-
very catkins ; each flower is merely
a single pistil with a forked stigma,
and, like a male flower, is supported
on a small honeyed bract. T'he
flowers appear in March, before
the leaves, and the catkins are very
conspicuous. They are visited by
bees for the sake of the honey and
pollen, pollinatioiwbeing thus effected.

In June, the female catkins are
ripe. Each ovary has now bec'onie
a fruit, which opens and liberates
the silky seeds. When the seeds
dry, their fine hairs cling together
so that a light fluffy mass is formed,
which can be blown to great dis-
tances by the wind.

The poplar. — The various poplars are also coiiipleiely
uiiisexKal, that is, any one tree bears either male or female
flowers, but not both. In this ('ase also the flow’ers appear
before the leaves ; but the flow^ers are pollinated by the aid
of the wind, t\ot by insects, and nectaries are therefore
not formed. The catkins are not very much like those
of the willows in appearance, but the fruit and seeds are

A II

—The Willow.

A, fiowennt; inale-bhoot ( x 1|)',

B, jiiaU* Hower with bjat'i

(nuic:njficil) ; C, female C(me ;
/h A, fcni.Tle flowers (majj;ni>
fic'd); A, fiuii (x§); (r, the
same m.'iKnified ; //, seed

(magiiiried).

152

AN INTRODUCTION TO NA’iuRE-STUDY

Fig. 122.— The Popl.ir. i, male catkin ( X §) ;
2, female catkin (xil); 3, male flower (X 2) ;

G>i-nalc flower (X4)‘i 5, the same in longi-
tuclTnal seitioii; 6, fruit; 7, the same after
opening ; 8, seeds ( X 3) ; g, diagram of male
flower.

very similar. Both wil-
lows and poplars are fond
of the banks df streams.
The English poplars are
graceful trees which can
be recognised at a dis-
tance by the manner in
which' the broad leaves
turn on their long stalks,
exposing the lighter-
coloured under - surface
at the slightest breath
of wind. This is especi-
ally noticeable with the
aspen or trembling pop-
lar (Fig. 122). The
Lombardy poplar is a tall,
stiff tree.

32. THE ELM, LIME, AND ASH.

1. The elm. — Notice the straight trunk, rough bark, and
slender branches of the common elm. Examine the flowers in
early spring and notice that each contains both stamens and
pistil. When do the flowers open? When do the leaves
expand ? Draw a leaf and a fruit. What is the use of the broad
plate of the fruit ?

2. The lime. — Observe the straight trunk, smooth bark, and
general pyramid shape of the tree. Draw a leaf, and notice that
it is pointed and is larger on one side of the midrib than on the
other. Notice that the flower stalks spring fropi leaves (bracts)
differing in shape (Fig. 126) and colour from ordinary leaves.
Draw one of these leaves with its attached flower stalk. When

eLm, lime, and ash

IS3

do the flowers* open ? Try to discover whether bees haunt the
flowers. Find out what is the use to the fruit of the long leafy
bract.

3. Tlie ash. — Look in winter iV the black buds and the
flattened tips of the twigs. When do the flowers open ? Notice

Fic,. 123 — The Elm

their rich purple colour. Examine a flower and make out the
two stamens and the pistil. Trace the formation of the fruit,
which is winged and hangs in bunches called keys. What is
the use of the wing ? When do the leaves expand ? Are they
simple or compound ? Draw one. What is its colour ? When
do the leaves fall ?

The elm. — The elm (Fig. 123) is usually a lofty tree,

154 an introduction TO NATURE-STUDY

easily recognised at a distance by its straight trunk, slender
branches, and rounded masses of foliage, d’he bark is
rough and very corky, 'i'h^ tree flowers early in the spring
before the leaves are ex})anded. The flowers are purple
and contain both stamens and })istil. Each fruit (Fig. 124)
is a flat plate with a rounded seed box in the middle ; it is
distributed by the wind. 'The seeds of the common elm do
not often ripen in this country. The leaves (Fig. 124) are

tin. 124. ~ The
Kliii ; leaves, flowers
and flint. 1, flower,
nii; bjaiM'l) (k-J); 2,
liianeh wilh leaves;
'I, a flower (\2); 4,
the same, cut through
longitudinally; 5, a
hull (a.-;).

rough to the touch, and have very prominent veins. They
do not fall until late autumn.

The lime. —'rhe lime tree (Fig. 125) has a straight
smooth trunk. The tree generally spreads at the base,
and tapers to a blunt aj)ex. The leaves are bright green,
hcarFsha[)ed, and ])ointed, and plainly larger on one side of
the midrib than on the other, 'bhe yellowTsh-green flowers
are in bunches, carried on a stalk which spjings from the
middle of a long, narrow bract (Fig. 126). • ddie flowxTs are
complete — calyx, corolla, stamens, and pistil being all

156 AN INTRODUCTION TO NATURE-STUDY

present — and are pollinated by bees, which ivisit them for
the sake of nectar, being attracted by the sweet scent.

The ash (Fig. 127) is yvery graceful tree, and its com-
pound leaves, with leaflets springing from the sides of
the midrib, give the foliage a characteristically feathery

Fig. 127. — The Ash.

appearance. The bark is ashen-grey in colour. The tips
of the twigs are curiously flattened, and the winter buds
are jet black. The flowers are small, with two purple-black
stamens and a pistil. They open in April before the leaves
appear, forming close clusters. The fruits are long and flat,
and hang together in bunches which are ‘ popularly called
keys. They are only detached by high winds, and are then

SYCAMORE AND HORSE CHESTNUT

157

blown to considerable distances. The leaves appear rather
late — about the end of May — and are shed early. They
are compound, each consisting seven or more leaflets
arranged in opposite pairs along the midrib, with a single
leaflet at the end.

The mountain ash or Rowan tree has leaves somewhat
like those of the ash proper, but in other respects it is quite
diflerent, as it belongs to the rose family (p. 103).

33. THE SYCAMORE AND HORSE CHESTNUT.

1. The sycamore.- Observe the size and g,^neral shape of
the tree. Examine the twigs in winter and watch the buds
open in spring. Draw a leaf. Why are the leaves usually so
sticky in warm weather? Notice the hanging sprays of green
flowers. Are both stamens and pistil present in the same
flower? Are the flowers visited by bees? Why? Follow the
development of the fruit. Draw a pair of fruits. What ia' dVe
use of the wing or> a fruit ? Do the fruits fall off themselves or
are they torn off by gales ? Look for seedling sycamores in the
woods ; also germinate seeds in garden soil and again observe
the various stages.

Compare the pla^ie^ .and notice the pyramidal shape of the
tree. The leaves are very similar in outline to those of the
sycamore, but the flowers are clustered into balls which dangle
on long stalks. In summer, pull off a leaf and observe how the
axillary bud is covered by the cup-shaped base of the leaf-stalk.

2. The horse chestnut. — Notice the general shape and method of
branching. These characters, the large buds in winter, and the
shape and size of the leaves in spring and summer, render the tree
easily recognisable at all seasons. Trace the connection between
the method of branching and arrangement of the leaves and
buds on the twigs. Note the date of flowering, and of the
unfolding and shedding of the leaves. Examine the flowers ;
are they pollinated by insects or by the wind? Trace the
development of the fruit.

158 AN INTRODUCTION TO NATURE-STUDY

The sycmore (Fig. 128) is one of the best-inown trees in
this country, and often grows to a great height « Its leaves
(Fig. 33) are large and fiA^.'-pointed, the main veins spread-
ing from the top of the leaf stalk. When young they are of

Fi(i. 128. — The Sycamore.

a beautiful red colour. In hot weather the leaves become
very sticky with a sugary syrup called honey-dew. The
sycamore is indeed a species of maple, and is closely
related to the sugar maple of North Amocica. In May,
the flowers hang from the twigs in drooping green clusters.
They contain both stamens and pistils, and are visited by

THE HORSE CHESTNUT

159

bees for the suke of the honey in which they abound. The
fruits or kejs (Figs, ijy and 4) occur in j)airs, or sometimes
three together. Each has a Hat, membranous wing, by
means of which it is easily transported by the wind.

In Scotland the sycamore is often called the plane. The
leaves of the plane and sycamore are somewhat similar in

IMG. 129. — I'he Chestnut.

shapt^ but the trees belong to different families. The
plane can be identified by its globular heads of flowers and
subsequent balls of seeds, which hang on long stalks from
the twigs.

The horse chestnut. — The horse chestnut differs from all
our other forest trees of equal size in bearing brilliantly
coloured and conspicuous flowers. 'Fhe flowers are complete,

i6o AN INTRODUCTION TO NATURE-STUDY

containing not only stamens and pistil, but also a calyx and
a beautiful pink or white corolla. The tree hj^s a striking
appearance at all seasons the year. In winter,* the thick
twigs, the large terminal buds, and the opposite lateral buds
already described on pp. 62-64 are very conspicuous, and
give an instructive clue to the method of branching. The
buds open early and the new shoots rapidly lengthen, so
that the tree is a mass of foliage whilst most neighbouring
trees are still bare. The leaves (Fig. 26) are compound,
consisting of seven large, spoon-shaped leaflets which spring
from a common point at the end of the leaf-stalk. The
flowers open in May. The fruit is ripe in October and
then falls to th^ ground, its prickly husk splitting into three
parts to liberate the rounded seeds. The leaves fall early,
leaving large scars (Fig. 38), which have some resemblance
to the hoof-marks of a horse.

34 CONE-BEARING TREES.

I. The Scotch pine. — Notice the shape of the tree : the tall
straight stern and rugged bark, and the dark tufts of foliage.
Does the tree bear leaves all the year round ? Does it ever
shed its leaves ? Are they shed at any special time of the year?
Examine a leafy twig ; observe that the leaves are needle-shaped
and come off in pairs. At the apex is a terminal bud which will
continue the length of the twig next season ; the lateral buds
below will grow out into twigs at the same time. Try to make
out which parts of the twig grew during last year, and which
during the two previous years.

Notice the cones. The young female cones (^, Fig. 130, i) are
erect, and their scales separate slightly in spring to allow the
pollen to enter. Afterwards they hang down (c) whilst the seeds
are ripening. Three years after pollination the scales come apart
again to let the seeds fall out. Examine the seeds from a ripe
cone and notice the attached wings (Fig. 1 30, 4). Examine cones

CONE-BEARING trees i6i

of various ages^ In spring look for the pointed cones of male
flowers (Fig. 130, i, ^^) which produce the abundant pollen.

2. The spruce fir. — Compare the spruce fir. Notice the conical
Christmas tree shape and the large spreading branches near the
ground. Compare the leaves and cones with those of the pine.

3. The larch. — Compare the larch with the pine and spruce.
Notice the drooping boughs, the alternate tufts of leaves, and
the small cones arranged in a row along the twig. Is the larch
an evergreen ?

Cone>bearing trees. — The cone-Vjearing trees, such as the
pines and firs, are true flowering plants, but of a type which
is very different from any hitherto described. The flowers
are peculiar, and form cones, the male floj^ers jiroducing
pollen and the female flowers ovule.s. I'he ovules, however,
are not enclosed in ovaries, but are naked, so that the pollen
gains access to the ovule directly, and is not received on a
stigma. The female cone consists very largely of smooth
scales, a pair of ovules being borne by each scale near '‘'c
base. The pollen, grains of these trees are rendered parti-
cularly buoyant by being blown out at the sides into little
air-filled bladders, and are thus easily carried by the wind.
When the pollen falls on the female cone, the grains slide
down the smooth scales and very likely come in contact with
the ovules at the bottom. Each ovule has a sticky drop of
gum at its end, and the pollen is caught in the gum. Such
pollen grains as roll off the upper scales are almost certain
to fall bn a lower one and reach the ovules.

The Scotch pine. — This is a large tree, with a dome-shaped
crown of foliage. The bark is rough and scaly. Its foliage
leaves (Fig. 130) are long and needle-shaped, and occur in
pairs, each pair being carried by a very short branch. The
leaves do not fall off each winter, as do those of most forest
trees, but remain on the branches for three years or more, so
that the younger twigs are clothed with foliage at all seasons.

N.S. L

i62 an introduction TO NAfURE-STUDY

The cones of male flowers (Fig. 130, t, a) are found at
the base of some of the shoots of the current year. The
female cones (Fig. 130, i, /f) are formed round the f/u/s of the
young twigs. They consist mainly of overlapping woody
scales, each being knobbed on its exposed surface and bear-
ing a couple of ovules
near the base, where it
springs from the axis of
the cone. The young
cones are erect, and
in spring (when clouds
of pollen are blowing
about) their scales separ-
ate slightly to admit the
pollen in the chinks
between them. After
pollination the scales
close again and the'
cone Ijangs down (Idg.
130, I, c). The ovules
receive the pollen in
Fu,. 130 — rhe Scotch Pine, i, br.'inch with Mav, but the actual

male («) and female (/>, r) concs ; r, com. ( '< 0 • /

2, two views of a stamen ( 2 ) : 3, scales heannt; Utlion, Or ' fertilisation,

two ovules (X2); 4, sc.'de with two seetls (</), i 1 -i

wing(/^), seed (c): 5, seed in longitudinal section (loeS IlOt take plaCC Ulltll

June of the following
year. The seeds become mature two years after fertilisa-
tion. When they are ripe each bears a thin wing which has
split off from the u[)per surface of the scale. The scales
now separate, and the winged seeds fall out, to be distributed
by the wind. When all the seeds have fallen, the empty
cones drop off the tree.

Owing to the length of time necessary for the ripening of
the seeds, cones of various ages may be found on the tree
all the year round.

CONE-BEARING TREES

1^3

The spnce fllr. — The spruce has a characteristic conical
shape, which. is familiar in Christmas trees. The branches
are long, and spread horizontally. ^ The foliage leaves are
needle-shaped and four-sided in section, but are shorter than
those of the pine, and are borne singly. The tree is ever-
green ” in the sense that the pine is so, that is, the leaves are
not shed all together, but gradually.

The method of pollination, fertilisation, and distribution
of the winged seeds is similar to that of the pine. In the
spruce, however, the seeds are ripe in October of the year in
which the cones are i)ollinated.

The larch. — The larch is a cone-bearer, and a near rela-
tive of the pines and firs, but it differs from thcim in shedding
its leaves annually. 1'he leaves are (as is usual in cone-
bearing trees) needle-shaped, but they are very thin and they
grow in tufts on short alternate spurs. 1'he cones arc small
and are arranged in a row on the twig. Their scales do not
fit so closely together as those of the pine and fir con^^s.
The larch tree has 'a conical form, but can readily be distin-
guished from the spruce by its d?vopwg boughs, and absence
of leaves in winter.

Gymnosperpis. — The pines, firs, and larches are neither
dicotyledons nor monocotyledons, but belong to a class of
plants which botanists ('all gymnosperms, in allusion to the
fact that their ovules are not enclosed in ovaries, like those
of other flowering plants, but are iiakcd, I'his is the most
ancient and primitive group of flowering plants known. In
fact they form a connecting link between higher flowering
plants and the group to which the ferns and horsetails —
which are still more primitive — belong.

164

AN INTRODUCTION TO NATURE-STUDY

EXERCISES ON CHAPTER VIII.,

1. What trees are the fiiy. to put on leaves in England? Which
flower before leafing? Wliich trees are the latest to come into leaf?
When do evergreens, fur the most part, change their leaves? (N.F. U.)

2. Describe the fruit and seed of four of our commonest trees,

explaining in each case how the seeds are distributed. (N.F.U.)

3. Make observations to find which of the following trees endure
sViade most readily — oak, beech, elm, sycamore, chestnut.

4. What do you suppose are the advantages and disadvantages of
shading and crowding tiees, as regard-s the quality of the resulting
timber ?

5. Study young pines and firs, and find out during which period of
life they grow mc/St rapidly.

6. Which trees have you found growing (^0 in heavy clay soils, [b) in
sandy soils?

7. Describe any observations upon six common British trees which

could be made during a walk in early spiing. (N.F.U.)

CHAPTER IX.

FRUITS: HOW SEEDS ARE SCATTERED.

35. PLANTS WHICH SOW THEIR OWN SEEDS.

1. The fruit of the wallflower.- -Examine wallflower fruits and
make out that each consists of the ripened pistil. Docs the
fruit open of ilsi'lf? How many chambers does it consist of?
Where are the seeds attached? Are tliey blown off at last by
the wind? Draw the fruit. It is called a siligua.

2. Compare with this the fruit of shephereV s piirse (Fig. CE;,
Tmd penj7y cress' (l'*ig. 132), and notice that they are of the type
of the wallflower fruit, but are much broader in proportion to
the length. Such a fruit is called a silicula. Draw.

3. The ftniit of the pea. — Examine a ripe pea-pod and com-
pare it with ip) the pistil of an unfertilised flower, {b) a half-ripe
pod. How many carpels have taken part in forming the pod?
How many seeds (peas) docs the pod contain ? Leave a pod
on the plant until the shell becomes dry, to find out how the
fruit opens. Does it open along one edge only, or along both ?
How are the seeds attached ? Such a pod is called a legume.
Draw it.

Compare and draw the legumes of the broad bean, French
bean., scarlet rit?i7U'r., laburnum (remember its seeds are
poisonous), and binrs foot trefoil. The legume of the bird’s
foot trefoil bursts open suddenly and scatters the seeds in the
air. Is the scattering of the seeds any advantage Why ?

4. The fruit of the field geranium. — Make out that five
carpels are grouped around a central rod. Examine fruits

i66 AN INTRODUCTION TO NAtURE-STUDV

which have opened. About noon on a bright, sunny clay gently
touch a ripe fruit with a small brush, and watch the carpels
spring back from the rod and jerk the seeds into the* air. Com-
pare and contrast this frui/ with a siliqua, silicula, and legume
respectively.

5. The fruit of the poppy. — Examine a poppy head. The
top of the fruit is the stigma. Observe below this a line of
small holes running round the fruit. Draw. Shake the fruit,
and notice that seeds fall out through the holes. Cut the fruit
across to see the large number of small seeds inside. How docs
the fruit hang on the growing plant? Does the wind shake it
and liberate the seeds ?

6. The fruit of the pansy and violet.- Watch the ripening of
the fruits on the plants. Observe that the ovary swells up into an
egg-shaped bodj' which afterwards splits into three boat-shaped
valves containing seeds. Try to make out why the seeds are
one by one shot out as the sides of the valves dry. Put a ripe
fruit before the fire and watch the process. Imitate it by
placing a pea between two flat rulers and pressing the rulers
tagether.

The origin of a fruit. — When the ovules of a flower have
been fertilised (p. 92) by the pollen tubes they change into
seeds which have the remarkable power of growing up — in
favourable circumstances -into plants Tesemblihg that which
produced the seeds. This is not, however, the only result of
fertilisation. Whilst the ovules arc changing into ripe seeds,
those parts of the flower — the stamens, corolla, and calyx —
which have finished their work wither and fall off, though
the calyx sometimes remains. Other parts— the pistil and
sometimes the receptacle (p. 90) - take on new duties, and
become gradually modified in order to protect or scatter the
seeds.

Thus, the tender wall of the pistil often becomes a woody,
leathery, or juicy seed-case ; while the receptacle, or top of
the flower stalk, may become fleshy and swollen with sugary

PLANTS WHtCH SOW TITFTR OWN SEEDS 167

pulp, as a bait. for birds and other animals. In any case we
give the name of fruit to all such altered and persistent parts
together >Aith the seeds which accompany them. A pea
pod, for example, is as truly \i
fruit as a plum, and a poppy-head
as a strawberry.

What a fruit is like depends to
a great extent upon the characters
of the pistil which gave rise to
it. If, for example, the pistil con-
sists of several separate carpels, the
ripened carpels or fruits will also
be separate. When, on the other
hand, the pistil is comj)osed of
united carpels, these will remain
united, at least until the fruit is
ripe. Then in some cases they
come apart.

The part of ^a fruit which is
derived from the walls of the
pistil is called the pericarp.

The fruit of the wallflower. —

After fertilisation .the stamens,
petals, and sepals of the wallflower
drop off leaving the pistil alone on
the top of the flower .stalk. 'The

. . , . . flowt-r { -c 5) ; Mhqua (xi);

pistil increases greatly in size (flig. c, siiiqua «)])eu.

131, y>) during the ripening of the

seeds. At last its wall (the pericarp) splits into two flaj^s.
These become free at the liottom, exposing a central plate
which bears the rows of seeds. When the seeds are (luite
ripe, a slight breeze is sufficient to shake them off, and they
fall to the ground to take their chance of finding a place
favourable for germination.

I68

AN INTRODUCTION TO NAIvRE-STUDY

A fruit with a dry pericarp, which opens of itself when the
seeds are ripe, is called a capsule. This patticular kind of
capsule — consisting of two carpels which coine apart at
maturity, leaving a central' partition bearing seeds — is known
as a Blliqua. When it is short in proportion to its length, as
in the shepherd’s purse (Fig. 62) and
penny cress (Fig. 132), it is distinguished
as a silicula.

The fruits of the pea tribe.— The pod

of the pea (Fig. 3) and its relatives is
a capsule of another kind. It consists
of one carpel only, and opens, when ripe,
along both back and front margins to
liberate the seeds. Such a fruit is called
a legume. In the young fruit the pericarp
is somewhat fleshy and succulent, but it
becomes dry during ripening. The legume
of the birds foot trefoil bursts open
suddenly, and throws the seeds to a
considerable distance.

The fruit of the field geranium (Fig. 133) is a long
capsule composed of five car^iels arranged round a central
column (A). When the seeds are ripe, the carpels suddenly
spring from the rod, remaining attached only at their upper
ends ( 7 ^), and fling the seeds into the air. The method
may be watched by stroking the fruits very gently with a
small brush, when they open in the manner described.
The experiment is most likely to succeed in dry, sunny
weather, about the middle of the day.

The fruit of the poppy. — The pistil of the poppy swells
during ripening into a large, globular capsule known as the
poppy head. The top of the fruit (Fig. 134) is the persistent
stigma. Just below this, a line of small holes like windows
runs round the head. As the fruit hangs inverted on the

Jig. 132.— Fruits
(siTiriilae) of Penny
Cress. (Nat. si/e.)

PLANTS WHICH SOW THEIR OWN SEEDS 169

top of the flower stalk it is shaken about by the wind, and the
tiny seeds fall but throu^ijh the windows.

The fruit of the violet or pansy. — I'he arrangement by
which the violet (Fig. 1 34) or pansy sows its seeds is most inter-
esting. After fertilisation the ovary swells into a great egg-

Fig, 134. — capsule of poppy; B, cross section of capsule (x^);
C, seeds.

shaped capsule, in the inside of which the seeds are arranged
in three rows. ^ When the seeds have become ripe and hard,
the capsule splits down the side along three lines, and is thus
divided into three parts. These open outwards, and bend

AN INTRODUCTION TO NATURE-STUDY

back as shown in Fig. 135. Each is a boat-shaped valve.
The seeds inside are thus exposed to the air, ’’and they soon
dry and beccjme ready for scattering.

Then the curved sides ^of each valve begin to straighten
and come together, and naturally allow less and less room
for the hard, smooth seeds inside. The pressure of the
sides of each valve on the seeds inside it becomes greater and
greater, until one by one they are shot out to a considerable
distance. If a ripe violet ovary he warmed before the fire

the whole operation may
easily be watched. The pro-
F cess may be imitated by
putting a pea between two
flat rulers and pressing the
rulers together, when the pea
may be shot to a distance of
several yards.

Why fmits are scattered. —

A flowering plant is practi-
cally confined for life to the
place where it first sprang
up, so that it is unable to
Fir,. 13=;. --Violet, /^.explosive fruit ; about and sdcct favour-

S, seecK heiiiR sliot out of fiuit. _

able situations for its off-
spring. On the other hand, if the seeds simply fell to
the ground beneath the parent plant, the seedlings would
generally be so crowded together that they would interfere
very much with each other’s growth. In addition, they
would often be under a great disadvantage, because the
jiarent plant would keep so much light from them. Hence,
very many plants have some special arrangement for
scattering their seeds, so that some at least of the seeds will
have a chance of falling in a place where they will obtain
plenty of light, air, and good soil.

SEEDS SOWN BY THE WIND 171

In this section we have studied examples of devices by
which plants sow their own seeds. We shall see next that
other plants call in the help of the wind and of animals.

36. SEEDS SOWN BY THE WIND.

1. The fruit of the dandelion.— Examine the manner in whicli
the tiny flowers of the dandelion are grouped together to form
the head (p. 113) ; and make out the various yjarts of the flower,
especially the ovary ~?i little white knob at the bottom of the
flower, and the calyx-iubc — forming a tuft of fine hairs above
the ovary. Trace the development of the fruits : the wathering
of the corollas and stamens, the elongation o^f the calyx-tube,
and the expansion of the tuft of hairs to form a paiachute.
Blow a dandelion “clock*’ (the head of fruits), and notice how
the parachutes float the fruits in the air.

Examine “thistle down” and contrast it with the dandelion
fruit.

2. Tlie flniit of the willow. — Examine the ri])encd catkins of
a female willow in. June, and notice how each fruit has split into
halves, which come apart and expose the silky seeds inside.
Pull a tuft of seeds out and dry them in the sun. Notice that
they wriggle and writhe about and gradually become entangled
together into a woolly mass, whic h is easily blown away.

3. The elm ftuit. — About the end of Ajiril look for elm fruits.
Notice the flat green plate (wing) with the rounded swelling
near the middle (Fig. 124, 5). Cut open the fruit and see that the
swelling is caused by a single seed. Mow does the flat wmg
aid in the distribution of the seed ?

Compare the winged fruits of the ash and syiaiiiorc (Fig". 137)-

Do these winged fruits drop from the trees easily, or are they
torn off by gales ?

Take a pair of sycamore fruits. Cut off the wing from one
and let it and an uninjured fruit fall at the same instant from a
height. Which reaches the ground first ? Why?

4. Pine and fir cones.— Examine and compare pine and fir
cones of various ages. Break open a ripe cone and see the

172

AN INTRODUCTION TO NATURE STUDY

scales with the pairs of naked seeds, each seed bearing a thin,
papery wing which has split off from the upper surface of the
scale.

Wind-sown seeds. — Many plants depend on the wind for
the dispersal of their seeds, and consequently the seeds are
provided with outgrowths of various kinds, which increase
the surface greatly without adding much to the weight, and,
acting like parachutes, offer increased resistance
to the air and thus prevent the seeds from
falling quickly to the ground. In some cases
the outgrowth is part of the pericarp, in
others it is an appendix carried by the seed
itself, while in the lime it is the bract upon
which the flowers were formerly borne.

The dandelion fruit. — 1 ’he fruit of the dande-
lion (Fig. 136) affords one of the best possible
examples of wind-dispersal. It will be re-
membered (p. 113) that what is commonly
called the flower of the dandelion is really a
head of perhaps 300 complete flowers : each
with a hairy calyx-tube, a yellow, strap-shaped
“ Clock of corolla, five stamens, and a pistil. When the
Fruhs^^(ii) flowers have been fertilised, the yellow corollas
and the stamens wither, the ovary increases in
size with the ripening of the single nutlet in its interior,
and each calyx-tube elongates until it is about an inch
in length, the tuft of fine hairs being still at its upper
end. The attachment of the fruit (Fig. 86, 4) to the disc
(receptacle) is so slight when the seed is ripe that a very
gentle puff of air is sufficient to overcome it. The tuft of
hairs at the upper end has by this time expanded until it
acts like a parachute, which supports the tiny fruit for a long
time in the air.

SEEDS SOWN BY THE WIND

173

The common thistle —a relative of the dandelion — also
distributes its fruit by means of a tuft of fine hairs derived
from the' calyx. In this case the hairs radiate from the
seed. Such “thistle down’" is commonly found floating
through the air in summer.

The willow fruit. — The catkins of the female willow are
ripe in June. Each catkin consists of a large number of
tiny pods derived from the ovaries of the flowers (p. 151).
Each fruit splits into halves, which bend back from each
other (Fig. 121, exposing the silky seeds within to the
warmth of the sun. The seeds (//) turn and twist about as
they dry, and gradually entangle them-
selves together into a light, woolly
* mass, which is easily blown to great
distances by the wind. The willow
and the dandelion, therefore, use
very similar devices to ensure the dis-
persal of their seeds, although these
plants are not at all nearly related.

The fruits of the elm, sycamore,
and ash. — These common forest
trees bear fruits with the seed attached to a flat plate,
which is an outgrowth of the pericarp (p. 167). In the
elm fruit (Fig. 124, 5) the plate is green and oval, and the
seed forms a rounded swelling at, or near, its middle. The
fruits of the sycamore generally grow in pairs (Ings. 33 and
137). Each half consists of a single seed with an attached
membranous plate, and the two seed boxes of each pair
are in contact. The fruits of the ash hang from the twigs
in bunches called “keys,” each fruit on a separate little
stalk. The plates which bear the seed are long, narrow,
and oval in shape.

It is plain that such plates, or wings, expose a relatively
large surface to the air and prevent the fruit from falling to

174

AN INTRODUCTION TO NATURE-STUDY

the ground as quickly as it otherwise would. The fruit
IS thus often blown to a great distance befoiv it finally
settles and the seed genyinates. The action of the wing
may be well shown by cutting off the plate from a sycamore
fruit and letting it and one with an attached wing fall at the
same ii:istant from a height. The seed without a wing
comes straiglit down as a pea would ; but the winged seed
.spins in the air and settles more slowly.

In the case of the round downy fruits of the lime, a
similar service is performed by the bract (E'ig. 126), upon
which the flowers were carried.

Pine and fir cones.— If a ripe pine, or fir cone is broken
open, it will be«*scen that each seed is attached to a thin,
papery wing (Fig. 130, 4), which has split off the upper sur-
face of the scab' bearing the seeds. T'he winged seeds are
shaken out of the cone by the wind, and blown away.

Trees alone bear winged seeds. — Winged seeds would
be useless to any but fairly high trees, because if they were
formed on the low plant they would fall to the ground long
before the wind could catch them properly. It is also
interesting to find that such seeds are generally attached so
firmly that they are only broken off by gales strong enough
to carry them a considerable distance.

On the other hand, the tiny plumed fruit of the dandelion
or thistle is so very light in comparison with the surface
exposed to the air that it takes ejuite a long time to fall even
a few inches.

37. SEEDS WHICH ARE SCATTERED BY ANIMALS.

I. Hooked fruits. --Examine ])lants of Z/rr// bcn 7 ict (wood
avens) in summer and autumn, and find the fruits. Brush your
sleeve against the fruits, and notice how they cling to the cloth.
Examine them with a lens and observe the hooks at the ends of
the styles.

SEEDS SCATTERED BY ANIMALS

^75

Compare goo^egrass (cleavers) and find the liooks on the
fruits.

2. Nuta-r-Exaniine a nut. Notice^ the sheathing

bracts at the base of the fruit. Crac^j: the nut and examine the
broken edge of the shell (pericarp) with a lens. Make out tlie
three layers which compose it. How many seeds are present?
Cut the seed (kernel) across and see that the bulk of it consists
of two cotyledons (Chap. L). Does the fruit open of itself, if
undisturbed ?

Compare the acorn of the oak. Trace the development of
the acorn from the female flower, noticing that the cup is
developed from a wrinkled disc surrounding the lower part of
the flower. Cut across the ovary in June and notice that there
are six ovules in it. In the ripe fruit observe that the cup
separates easily from the nut. Remove the shfell (pericaip) of
the nut. How many seeds does it contain ? What do you
think has become of the other five ovules ? Cut through the
seed and observe the two cotyledons.

Compare the fruits of the bccch. Notice that they arc three-
sided nuts (each being a seed enclosed in a v\oody pericarp) ;
and that two nuts occur together, surrounded by a l^ristly woody
cup which splits, wlien the nutb are ripe, into four valves.

3. Stone fruits, — E'xarnine a ripe plum. Cut it open and
crack the stone to see the single seed. Notice that the
pericarp consists of thiee layers as in the hazel nut, but that
here the middle layer is soft and fleshy, and the outer layer is
the “skin.” The stone is the inner layer of the ])ericarp. Is
there any special means of liberating the seed ? Compare the
cherry^ and examine the seed and the three layers of the
pericarp.

Examine the fruits of the blackberry and raspbc?'ry^ and
observe that each consists of several small stone-fruits ai ranged
on the receptacle.

4. Berries. — The gooseberry . the stalk at the bottom
of the fruit, and, at the top, the withered remains of the calyx.
Cut across a hajf-ripe gooseberry and observe the ..hick, flesh)'
pericarp enclosing the seeds. Treat a ripe gooseberry in the
same way, and observe that the pericarp has now for the most

176 AN INTRODUCTION TO NATURE-STUDY

part become a soft pulp, in which the seeds are embedded.
The rest of the pericarp is a membranous skin. Is there any
special means of liberating the seeds ?

Compare grapes^ ciirran\s^ oran^e^^ and vegetable marrow
fruits, and notice that the structure of these resembles that of
the gooseberry.

5. The apple. — Cut across the receptacle of the flower
(apple blossom) and notice how the five carpels are
buried in it (p. 106). Trace the formation of the fruit, and
see how the receptacle becomes larger and larger during
ripening. At the top of the ripe fruit observe the withered
remains of the calyx. Cut the apple through across the middle
to see the core. This consists of the horny walls of the five
carpels and the contained seeds (pips). From what part of
the flower is tlie fleshy, eatable part of the apple derived?
Compare ^e^pear.

6. The rose hip. — Examine fruits of the wild rose. Notice
that they are urn-shaped. On the flat rim of the urn observe
the five scars left by the sepals (or, in some cases, the sepals
themselves). In the opening of the urn see a tuft of greyish
hairs. Cut the fruit down from top to bottom through the
middle to see the thick, fleshy wall of the urn and the contained
millets, f'rom what part of the flower is the flcsliy wall of the
hip derived ? Examine a nutlet. What does the tuft of hairs
seen in the mouth of the urn consist of? Open a nutlet with a
needle and pick out the seed.

7. The strawberry. — Cut a strawberry down the middle and
notice at the base the persistent calyx, in the inside the fleshy
receptacle, and on the outside the yellowish nutlets. Open a
nutlet with a needle and pick out the seed.

The help of animals. — It has been seen in Chapter VL
that insects play a very important part in the fertilisation of
many flowers. Very many plants also call in the aid of
animals at a later stage for the dispersal of the seeds, and
the devices by which this aid is obtained are often very
ingenious.

HOOKED FRUITS AND NUTS

177

Hooked fruits. — Sometimes after a country walk the
reader has probably found small fruits and s(^ds sticking to
his clothes. They have become attaclied to the cloth by
means of small hooks which they 'carry. The fruit of the
herb bennet (wood avens) is a good example of this
device. When the stigma of the fruit breaks away, a little
hook is left at the top of the style (Fig. 138). Goosegrass
or cleavers— a common hedgerow
plant — and many others have also
hooked fruits. Sheep or cattle,
grazing near such plants are very
likely to brush against them and
carry off the fruits and seeds in
their hair. They may not again
reach the ground until they have
been carried far from the place
where they grew.

The position of hooked fruits. —

It is evident that t,hese little hooks
would be (]uitc useless if the fruits
grew out of the reach of animals.

Such hooked fruits are never found,
for instance, on high trees.

Nuts. — A fruit whif:h has a dry, woody pericarp and does
not open of itself is called a nut. The fruits of the hazel,
oak, and beech are good examples. The shell (pericarp) of
the hazel nut (Fig. 139) is composed of three layers, and
encloses a single seed, or kernel. 'Fhe nut of the oak
(Fig. 113) is called an acorn. Its lower part lies in a cup
developed from a wrinkled disc by which the lower part of
the female flower was surrounded. When the fruit is ripe
The nut easily separates from the cup. The acorn contains
one seed only, which consists largely of two swollen cotyle-
dons. If the ovary of the female flower of the oak is cut
N.S. M

Fir;. ii8. — /I , Afjjxrcfj.Ttc Fruit
of Wood Avcms (nat. si/»*) "> niosl
of the stieui.is linve \)rokcii off.
a, a, n, fruits with stictmas still
attached ; r, calyx ; slru;le
fiuit with stictma still attached
(m.iquifieri) ; (', single hooked
fruit after loss of stigma (magni-
fied).

f7S AN INTRODUCTION TO NATURIvSTUDV

across in June six ovules are found in it. A§ in the case of
the hazel only one ovule is allowed to reach maturity ; the
rest are sacrificed in order that the remaining olie may be
more perfectly develope(!l. In the beech, two three-sided

Fig. 139. — A, gyoiip of Hazel Nuts ( x t) ; /?, lonukiulinal section of fruit.

nuts occur together, surrounded by a bristly, woody cup,
which splits into four valves when the nuts are ripe.

^ The dispersal of nuts. Squirrels and other nut-eating
animals are instrumental in the dispersal of the seeds in a

Fn. i.|') A, Plum; />, lonixitudinnl section; C, cross section;
J/, hn, ontci, middle, and innei layeis of pericarp ; A', seed. (.X^.)

somewhat indirect manner. Tdiey have a habit of storing up
nuts and seeds in holes ; but in their active life these
animals often forget where their larder is. 'Fhc seeds, thus left
to themselves, sprout and grow into trees. The unripe nuts
of the beech are protected from the attacks of squirrels by
the hard bristles on the outer husk.

STONE FRUITS AND BERRIES

179

Stone fruits.-f-A ripe plum (Fig. 140) or cherry (Fig. 77),
like a nut, ^consists of a seed and a pericarp j but here the
pericarp is specially modified to tt^ipt animals and at the
same time to protect the seed from them. The inner
pericarp-layer is a hard, woody shell called the stone ; the
middle part swells up to form a juicy, sweet
mass ; while the outer layer constitutes the
“skin,” and is often beautifully coloured.

Blackberries (Fig. 141) and raspberries consist
of several small fruits of the plum type, whic h
arc arranged round an axis derived from the
receptacle of the flower. O

Berries. — The gooseberry (Fig. 142) is a tyj^u* of this class
of fruit. It contains several seeds. 'The ])ericarp is thick
and fleshy before the fruit is ri[)e, but during ripening the
greater part of it becomes a soft, sweet pulp in which the'^'
seeds are embedded. The rest of the pericarp is a
membranous skin. Grapes, currants, oranges, and vegetable
marrow fruits are a*lso berries. The vegetable marrow has

I'K.. >41. —
P.lackbcrry.

obviously a general resemblance to a half-ripe gooseberry
but is on a much larger sc'ale.

The apple — In the apple (Fig, 143) we have an examj^le
of a fruit in theTormation of which the receptacle has taken
a large share. Even in the flower, the five car})els of the
pistil are buried in the receptacle, and as the seeds (pips)

AN INTRODUCTION TO NATURD-STUDY

ripen, the receptacle swells until it composes' the greater part

of the fruit ?nd nt last becomes sweet and fleshy, d'he

carpels with the contained seeds constitute the' core. The

Fig. 143. — ,4, Apple; B, lonGjittidiiial sei'tion ; C, mw section. (/|.)

withered sepals are still to be .seen at the top of the fruit.
The structure of the pear is (juite similar to that of the
apple.

The fruit of the wild rose I'he fruits of the wild rose
are called hips. They are urn-sha])ed, and on the flat rim of
the urn five scars sIkjw the former position of the sepals.

Fig. 144.—^', Strawberry; B', longitudin.il section; carpel,
swollen receptacle. (\^.)

In some cases the sepals themselves have remained. The
narrower mouth of the urn is filled by a tuft of greyish hairs
which, when the fruit is cut open, are seen to be the styles
of the carpels, 'fhe carpels are hairy, and stand on the

WHY SOME FRUITS ARE SWEET

tSi

bottom and sid^s of the urn-cavity. Each carpel contains a

seed. Coniparison with tlie flower shows th^tbe red, fleshy

urn is the developed receptacle. •

The strawberry.— In the strawberry (Fig. 144) the eat- ^

able part of the fruit is again the swollen and juicy receptacle.

In this case it has grown up on the ifiside of the carpels —
the little, yellow nutlets (car-
pels) lying on the surfac'c.

Each carpel contains a seed.

Why some fruits are
sweet. — The deli (ions fla-
vours of sweet fruits have
been developed as baits for
the allurement of siu'h ani-
mals as are likely to scatter
the seeds to the best ad
vantage. Consider such
fruits as cherries, currants,
and rose-hips lliids such
as thrushes — find them very
nice to eat, and are ready
to carry them away to con -
sume at their leisure The
birds eat the sweet, fleshy
part, but in the case of a

stone-fruit they drop the (aT) ' ^

stone and leave the seed

to germinate. A seed which is in danger of being swallowed
is either hairy like the rose-carpels (and therefore rejected
because it irritates the mouth unpleasantly), or it is enclosed
in a hard or horny case, upon which the animal’s digestive
juices are unable to act. When the seed is dropjied it is no
worse for its experience, and with good luck glows up into
a plant.

182

AN INTRODUCTION TO NATURE-STUDY

Eatable fruits generally conspicuous.^In order that

birds and olh\T animals may easily find the luscious fruits
which they may eat as a reward for scattering the seeds, such
fruits are almost always displayed very conspicuously, and
are brilliantly coloured. Oranges, plums, red currants,
apples, etc., illustrate this fact well. Red is perhaps the com-
monest colour of eatable fruits, because it contrasts so
strongly with the green colour of the foliage (I'ig. 145).

EXERCISES UPON CHAPTER IX.

1. Name and define the <iitferent kinds of self-oj^ieninjT fruits. Fiom

what coinuioii pCuils could you collect exam})les of lliese during an
Autumn walk? (N.F.U.)

2. Describe nny rough, ])rickly, or hairy seeds or fruits, explaining

the form and nature of the outgrowths and their use. (N.F.U.)

3. What wild fruits and wild lloweis w’ould you ex})ect to find in

September in youi part of the country? In what kinds of places would
you look for them? (N.F.U.)

4. Describe and draw the fruit of a field geranium, and point out the

uses of some of its peculiarities. (1898)

5 Describe the seed vessels of a jinnsy. Draw one entire, and also
burst open. IIow^ does it scatter the seeds? (1898)

6. Shortly describe the fruit of an a])plc or pear, and of a cherry or

plum. I’oinl out the chief ditferences between th('m. (1901)

7. How aie the seeds of cherry, field gcianimn, and pine or birch

dispersed? (1901)

8. Give e\am])les of seeds which are dispersed by the aid of birds
or other animals, explaining in each case how' the dispersal is effected.

(1893)

9. Why is it an oilvantaije to bome fruits to be (a) brightly coloured,
(/^) sweet ? Give examples.

10. A school museum contains, anumg other things, some dandelion

llutf, a dish of marrowfat peas, a few' nodules of garlic, and some haw-
thorn berries. How could you employ these to illustrate a lesson on
plant germination ? (Ceitificate 1903)

CHAPTER X.

FERNS AND HORSETAILS.

38. FERNS.

r. The male-fern, — (a) I /ain't of ^i^rowih- In •summer dig up
a plant of the common male-tern (Fig. 146 ) and wash the
soil from the roots. Make out the short, stumpy, creeping
stc77i^ covered with the hairy bases of old lea\es ; the slender
matted rooi:^ springing from the leaf-bases ; the large, com-
pound leaves Qx f7‘ 071 (Is of the current )'Ccir, and the coiled young
leaves which hav^e not yet exf)anded.

(/;) /’//c --Remove the large lea\es, leaf leases, and roots

from the stem, and examine it. Notice how the youngest leaves
are grouped round the apex of the stem. Cut a('rf)ss the other
end of the stem, and notice the cut ends of the toiiduciuii!;
strands embedded in a softer <^7'onn(l-tissi(C. Cut the stem in
halves lengthwise and carefully scrape away tlie ground-tissue of
one half to see how the harder conducting strands arc con-
nected together. If you spoil this, try again on the other half,
after boiling it until it is softened.

(c) 'rite lea7'es . — Make a drawing of one of the expanded
leaves. Notice that the leaf consists of a number of Icatlets,
and that these are again cut u]) into segments, or are at least
deeply lobed. Notice the browm hairs clothing the leaf-stalk
and the midrib.

Notice the c^ozier-like coiling of the young fronds, and make
out that when they uncoil the inside of the coil becomes the
upper surface of the leaf.

i84 an introduction TO NATURE-STUDY

(d) The reproductive of'gafis . — Examine the lower surface of
full-grown fronds, and notice the brown rounded patches. Dry
some leaves bcaj^jing these patches and shake them over a sheet
of paper. Collect the brov^n dust which falls from the patches ;
it consists of minute grains called spores.

(e) The profhallus.- ^ow some spores on damp soil sheltered
from the direct rays of the sun. Keep the soil moist, and notice
that in a few weeks the spores have grown into small, flat, green,
heart-shaped plants. Each of these is called ^prothaUus. Pick
off prothalli of different ages with a needle, float them in water,
.and comj)are the various stages of growth. In old prothalli
notice a young fern ])lant springing up from the lower surface.
Observe that as these become larger the prothalli which bear
them shrivel up and die.

2. The bracker fern. — Dig up a bracken fern, wash the earth
from the roots, and compare it, point for point, with the male-
fern. Notice :

{a) The long cylindrical, branching, underground stem. Does
it lie deeper in the ground than the stem of the male-fern? Cut
the stem across and compare the section with Fig. 148, noting

(i) the two concentric rings of separate vascuhir stra?ids' {s).

(ii) The stfr?iQthenin^ utaicriaJ., arranged a brown zone {Ip')
just below the skin, and as an incomplete ring (//) lictween the
two rings of vascular strands, (iii) 1'he softer ^round-tissue
(A), in which the vascular and strengthening strands are
embedded. Draw the external appearance of the stem (natural
size), and also the cross section (4 times natural size).

{b) The roots. — Describe the roots. Do they appear to arise
from any particular region of the stem ?

(c) The leaves . — From what part of the stem do the leaves
arise? How many come up each year? What is the appear-
ance of a young leaf before it expands? How does it differ
’ from that of the male-fern ? Draw a young leaf, and also an
expanded one. Is the leaf simple or compound ? Does it
branch ? Does the leaf of the male-fern branch ?

{d) The spores.— the under side of the leaf, and
notice the absence of the brown patches seen m the male-fern.
Notice that the edge of the bracken frond is folded over like a

FERNS

i8s

hem. Dry a frond, and then run the point of your pencil under
the fold and observe the brown dust (spores) which is removed.

{e) The 'prothalH . — Sow some bracken spor « on damp earth
and keep in a shaded place. Notice »that the prothalli produced
are very similar to those of the male-fern. Watch their develop-
ment and the growth, on old prothalli, of a new generation of
ferns.

3. The hart’s tongue fern. — Examine the hart’s tongue fern,
and notice how it differs from the two previous types. Are the
leaves simple or compound ? Observe the brown trenches on
the lower surface of the leaf. Try to get out some spores by
running the point of a pencil along the trenches of a dried leaf.
Sow the spores and try to raise prothalli.

The daily life of a fern. — The everyday life of a fern is
very similar to that of a flowering plant ; for the organs by
which it obtains food are — broadly speaking — of the same
type. Ferns arc lovers of damp and shady situations. The
plant obtains its mineral food from the soil by means of its
roots ; and its spreading green leaves, or fronds, enable it,
with the help of the sunlight, to decompose the carbon
dioxide of the air and to build up starch, sugars, and other
carbonaceous compounds.

The male-fern. — The common male-fern (which, by the
way, has no sex whatever) may be taken as a type of the
group. It o('curs abundantly in woods and hedgerows.
The stem, or rhizome, is short and stumpy j it grows obliquely
upwards, and does not branch. It is covered with old
leaf-bases, which are clothed with brown, scaly hairs. The
stem consists of a rather soft ground-substance, in which
is embedded a hollow cylindrical network of conducting
strands. In a cross section these appear as a somewhat
irregular ring of dots (Fig. 146, 2, a). When the soft ground-
tissue is carefully scraped away, the network of strands is
left as a skeleton, with large diamond-shaped meshes.

i86

AN INTRODUCTION TO NATURE-STUDY

The thin wiry roots spring from the ba^s of the leaf-
stalks, just whe^e these come off the stem.

The leaves or fronds ♦.of the male-fern arise near the
growing-point (the upper end) of the stem. Leaves of
almost all ages are present. Those which surround the

Fig. 146. — The Male-Fern, i, Illustration showing general habit ( XtV)*

а, young leaves ; 2, cross section of stem showing conducting bundles n I
3, portion of leaf; spore-boxes ; a, co\ering scale : 4, loiigitvulinal, and
5, Cl OSS section of group of spore-boxes ; a, leaf; S, scale ; c, spore-boxes :

б, a single spoi e-box ; a, stalk ; c, spring ; d, spores.

growing-point are mere rudiments ; while slightly older ones
(Fig. 146, I, a) are tightly rolled up into a coil. During their
growth the coils unfold, the inside of the coil becoming the
upper surface of the leaf. A fully-expanded leaf is roughly
triangular in shape. The leaf-stalk and the midrib are
covered with brown, scaly hairs ; and the blade of the leaf is

FERNS

187

divided into several distinct leaflets, which are arranged on
the midrib in two rows. 'The leaflets am also in many
cases suH-divided into separate segments. '

The spores. — On the lower ‘surface of many of the
segments of a male-fern frond may be seen a number of
small, brown, kidney shaped scales (f'ig. 146, 3, a). Each
scale is attached to the leaf by a short stalk, and the struc-
ture thus bears a rough resemblance to a little umbrella.
Attached to the bottom of the short “ handle ” of the
“umbrella” are several tiny boxes, somewhat like pill-boxes.
These are shown at h (Fig. 146, 3), and highly magnified at 4
and 5. Fig. 146, 6, represents a single box, more highly
magnified. When ripe, each box contains about fifty minute
grains, which may thus be likened to the pills in the pill-
boxes. These “ pills ” are called spores. Summing up thus
far, we may say that the spores are formed in spore-boxes,
which are attached by stalks to the lower surface of the
frond, each group of spore-boxes being covered by a pro-
tective scale. ,

The scattering of the spores. — When the spores are ripe,
each box (Fig. 146, 6) becomes dry, and is ultimately burst by
the sudden straightening of a spring (r) which is coiled round
its edge. The force of the uncoiling of the spring is
sufficient to jerk the spores (d) out of the box into the air,
and they may be carried for some distance by the wind
before they at length reach the ground. Once there,
however, each spore, under favourable conditions, begins to
grow, and gives rise to a plant which, curiously enough, is
not in the least like the parent fern plant which produced
the spore.

The difference between a spore and a seed. — It is
important to notice that the spore is produced by a purely
non-sexual process. In this respect it differs widely from
the seed of a flowering plant, which, it will be remembered

AN INTRODUCTION TO NATURE-STUDY

1S8

(p. 92), results from the union of the living matter of a pollen

grain with that of an ovule.

The prothallue. — The n^w plant, which is produced when
a fern spore germinates, is called a prothalliis (Fig. 147, A).
It is a flat, fllmy little plant, of the form which is generally
called heart-shaped. It has neither stem nor roots, but, as
it contains green colouring matter like that of leaves, and as
it puts out on its lower surface little hairs (r/i) which take up

watery solutions from the
soil, it is in no danger of
starvation, and is quite
capable of taking care of
itself and leading an inde-
pendent existence. This
tiny plant (a large fern pro-
thallus is perhaps half the
size of a 3d. j)iece), in con-
trast with its parent, pro-
duces sexual organs. Some
of these organs (an) give
rise to male cells and others
(ar) to female cells. 'The
male cells are excessively
small, and can only be seen by high powers of the micro-
scope. When they are ripe they swim about in a drop of
rain or dew, as if they were little animals, and find their
way to the female cells, which they fertilise. The embryo
which results from the union grows up (Fig. 147, /•') into
an ordinary fern plant, one being borne by each prothalliis.
In its young stages it is parasitic on the prothallus, i e. it
depends entirely upon the prothallus for its nutrition \
but it soon develops a little leaf {b) and a , root (re^), and
henceforth feeds itself. When the young fern is well
established in independent life, the prothallus shrivels up

Fig. 147. — The Male-Fern. A, Pro-
thallus seen from below ; male organs ;
ar, fema'f- orc:r'.'- ; rh, hairs. A’, Piothullus
witli b 111 attached to it ; b, the iirst

leaf ; iv^ the primary root (about 5
times nat. si/e).

FERNS

189

and dies. The subsequently-formed roots of the fern are

not branches of the primary root, but spring from the
bases of Ihe leaves. ^ ^ J

Alternation of genera-
tions.— In the life-history of
the fern there are thus two
very different generations.

The first generation— the
ordinary fern, which is non-
sexual — produces, by means
of spores, the sexual genera-
tion, called the prothallus.

The prothallus gives rise,
in its turn, by a sexual pro-
cess, to the obvious fern

plant Ibach generation Fig. 148. — Cross section of underground
,1 c 1 1 , btem (rhi/ome) of Bracken P'ern. s. Con-

therefore reseinblc.s, not its strengthening tissue ;

parent, but its grandparent ; c (X7.)

The bracken qr brake fern differs in several respects from

the male fern. Its
cylindrical stem (rhi-
zome) creeps along
horizontally beneath
the ground, branch-
ing at intervals, by a
division of its grow-
ing point into two.
Conducting strands
run along the stem
and into the leaves
and may be seen in
cross section (Fig.
148, s) to form two

Fig. T49.— Leaf of the Bracken Fern. (X^.) SOmewhat irregular,

I go

AN INTRODUCTION TO NATURE-STUDY

concentric rings. Strands and plates of ; strengthening
tissue (/) accoin^)any them, and a cylindrical zone (//) of
similar material also occurj just beneath the outside skin (e)
of the stem, line great advantage of having sup])orting
structures arranged as hollow cylinders has already (p. 72)
been referred to. The rest of the stem consists of softer
packing or ground-tissue, in which starch is often stored.

The sappy stalk of a young bracken leaf is very sturdy ;

Fif, i>5o. - Hart’s sct tion Uuou^h the feilile portion of a leaf;

Tongue Fern, (a^) .'A', spore-boxes; /, protecting flaps (X25.)

when it is only six inches high the stalk may be already halt
an inch across at the bottom, and half that thickness where it
curls over at the top to form a ('rook. The end of the leaf-
stalk divides into thret', each bearing a frond which, at this
stage, is coiled up tightly, locjking somewhat like a green
caterpillar. At a later staf^e, the middle one of the three
branches commonly divides again into three, and the branch-
ing may continue until the fully expanded leaf (Fig. 149) is
very complex. The spore-boxes and contained spores of the

THE COMMON HORSETAIL 191

bracken are very similar to those of the male fern, but tliey
are not collected in patches, like those shown in Fig. 146, 3.
Instead, they are ananged in a ro\y along the margin of the
lower surface of the frond-segmeht ; and the margin is
turned over— like a hem — so as to cover them in.

The spores are liberated in the usual way (p. 1S7) when
ripe ; and each germinates, under favourable conditions, to
form a sexual prothallus. lurch prolhallus gives rise to an
embryo, which is at first jiarasitic upon it, but presently
grows up into an ordinary bracken.

The hart’s tongue fern (Fig. 150) has simple and un-
divided leaves, which, as usual, bear siiore-boxes upon the
lower surface. In this case the spore-boxes i^re produced in
trenches, which appear to the naked eye as oblique brown
lines. Each trench is covered in by a pair of thin flaps
(/, Fig. T51). The life-history closely resembles that
already described for the male fern and bracken.

39. THE COMMON HORSETAIL.

1. Habit of growth. - Carefully cV\^ up a plant of the common
horsetail. Notice (^f) the deep, eiaa ping, underground .vAv;/.? ;
(d) the thin wiry r(}0/s springing from the stem ; (c) the two
kinds of upright shoots or Iiauhns : one kind (Fig. 152) — to be
found in summer— being thin, and giving rise to tiers of green
branches, which come off like tlie ribs of an umbrella ; the other
kind (Fig. 153), coming up in March, being paler in colour,
without branches, and bearing little coiks at the aj^icx.

2. The underground stem. Make out that the stem is dis-
tinctly divided into nodes-- marked by toothed Icaf-shealhs —
and internodes. Does it branch ? Notice that some of the
branches are swollen, forming tubers.

3. The roots. — These are thin and wiry, and come off fiom
the stem. Do they come off at-tlic nodes or at the internodes?

4. The branched haulms.— Observe that each is divided into
nodes — marked by toothed leaf-sheaths — and internodes. Arc

192

AN INTRODUCTION TO NATURE-STUDY

the internodes smooth or ridged? From whr.t parts of the
haulms do the latci'ul hnuiches arise? Carefully tear down a
leaf-sheath to sc-^ its relation to the branches. Notice that
the branches themselves branch repeatedly. What is the colour
of the branches ?

5. The cone-beaxing haulms. — Do these haulms appear earlier
or later than the others. What is their colour? Does a cone-

Fig. 152. — Sterile Haulms of IlDrseiail. Fig. 153. — Fertile Haulms of Horsetail.

bearing haulm give rise to branches at the nodes? Examine
the cone with a lens and see that it is coveted with hexagonal
scales. Does the hexagonal shape allow the scales to be more
closely packed ? Take off a scale with a needle and notice,
with the help of a lens, the spo?r-bores attached to its inner
surface.

6 . The prothallus. Dry a ripe cone and shake it over paper
to collect the spores. Sow these on moist soil, and try to raise
prothalli.

THE COMMON HORSETAIL

193

The general appearance of the horsetail — The common
horsetail {F\g. 154), which may be found in hedgerows and
cornfields, .is' not in any respect showy. It yarely exceeds a
few feet in height, and does not*iittrart attention by any
display of bright colours. The plant has stiff, jointed stems

Fig. 154.-— Common Horsetail, (xj.) i, Fertile haulms, terminatini^ in
cone.s (tf-L 2, a steule hanlni , n, tubei.s : sv^ale (.f ts.iie with spoie-

boxes (mag.) : 4, scale with ruptured spoi e-boxes (nuig.) : 5, 6, 7, spore>
(mag.),

or haulms, standing gracefully erect and bearing rings of
small united leaves at intervals. The brant hes arise jqst
above the leaves, and alternate with tluan : several coming
off at each level, .somewhat like the ribs of an umbrella.
T'he whole plJint has thus a rather stiff and formal
aspect

194

AN INTRODUCTION TO NATURE-STUDY

The haulms are very plainly of two kinds ; for some,
which are of a pale colour, do not branch, and are de-
veloped merely to bear the pretty little cones (Fig* 154, i, a)
which appear at their u|iper ends. As the purpose of the
cones is to give rise to the next generation, the haulms
which bear them may be called the fertile haulms. 'They
will be described presently, when the rejiroduction of the
plant is considered.

The sterile haulms. — 'The erect branching shoots
(Fig. 154, 2), bear no organs of reproduction, and are hence
referred to as the sterile haulms. T'heir work is to provide
the whole })lant with carbonaceous food, and it is on this
account that their branches are of the characteristic green
tint. In most green plants the manufac'ture of carbonaceous
food (Chapter 111.) takes place mainly in the leaves. In the
horsetail, however, the leaves are small and of very little
im])ortance in this respect, and the work is carried on by
the sterile haulms and their branches.

The underground stem and roots - -A large part of the
horsetail plant is hidden beneath the surface of the ground,
and often penetrates to a great depth. In ordinary language
these underground parts are called roots, d’hey are, how-
ever, subterranean stems, as is siiown quite plainly by the
fact that they bear small leaf sheaths like those on the
stems above ground. In ihe common horsetail the under-
ground stems often become swollen in parts by the formation
of /i^/jers (Fig. 154), as is the case with the potato. The
true roots are very slender and thread-like, and spring
from the nodes (p. 45) of the underground stems. They
penetrate the soil in all directions, seeking for water, which
they take up by the fine hairs which clothe them, like
velvet-pile, a little behind their points. The stem and its
haulms, like those of grasses, are stiffened by silica^ which is
deposited in the outer layers. This is of course obtained

THE COMMON HORSETAIL

195

from the soil. ' It is not absolutely necessary to the life of
the plant, hut it is nevertheless very useful, as it enables the
haulms to stand upright and spvead outUheir branches
to the light and air.

The sterile branches aie thus concerned with the horse-
taiFs daily life, d'he roots provide it witli water and mineral
food, and the green branches suj)})ly the necessary car-
bonaceous matter. Stem, branches, and roots are permeated
with a complete S3^stem of canals, through which the food
substan('es find their way to the various centres of activity.

The reproduction of the horsetail. - It has been seen
that some of the haulms do not bear branches, ])ut are .set
aside for the [irodiu tion of the cones. 'Fhete fertile haulms
come up in March, before the green sterile' haulms appear.
Wdien the cones are carefully examined they are s(^en to be
covered by a number of shield-shaped sc'ales. To the
inner side ol each s('ale(Mg. 154, 3, 4) are attached from five
to ten boxes, eacli containing a large number of little grains
or spores. T'he boxes burst open when tliey are ripe, about
the end of Marc'h, lilxjrating the spores ; and the fertile
haulms, hnving performed the one duty for which they were
developed, at once die down.

If the spores fall in a favourable situation they geiminate,
and each gives rise to a new [ilanl. d'he new plant is,
however, not a horsetail, but a small filmy prothallus, some-
what like the })rothallus of a fern. Some of the prothalli
produce male ('ells, while others give rise to female cells.
When the minute male cells are ripe, they arc set free, and
are able, by means of f nt.', lashing threads, to swim towards
the female cells of a neighbouring prothallus, through a dr(3p
of dew or rain. T'he two cells fuse together and give rise to
a little emtoryo, which in due course grows I'p into a new
plant — an ordinary horsetail with stems and branches and
roots like its grandparent.

AN INTRODUCTION TO NATURE-STUDY

196

The advantage of an alternation of generations. — The

iife-history of the horsetail is evidently very similar to that
of a fern, each exhibiting a well-marked alternation of
generations. T’here is reason for believing that the
prothallus-generation is the original form, and that the
ordinary fern and horsetail were developed
simply to scatter spores at intervals, and so
to give new plants the advantages of fresh
soil.

Living and extinct horsetails.— None of
the british horsetails is of great height,
although one species may attain to six
'^eet. Some of the tro[)ical members of the
family, however, are very much larger than
this, reaching even forty feet. In spite of
the last-named fact it is quite plain that the
horsetails have had their day, and are dying
out. If we wish to form an idea of what
they were at the height of their prosperity,
we must carry our minds back to the long
distant age when our coal was being formed ;
when sf) much of this country as then existed
y j low-lying swamp, covered with exuberant

amitc-: aiTextinct vcgctation. Then the horsetails and their
!VorWuiK(^u‘,!ily relatives were stately forest trees, and at
the head ot the vegetable kingdom. Some
of them towered to a height of over ninety feet. Nor did
mere height constitute the only difference between them and
their degenerate descendants. Many of these old-world
giants had already found out the device, since invented
alresh by more modern plants, of thickening their stems and
roots with secondary wood, and of giving rise to bark like
that of our present-day forest trees. The wood of these
Calamites (Fig. 155), as they are called by geologists, had

FLOWERLESS PLANTS

already reached much the same stage of development as is
found to-day in such a tree as the yew. The cones often
show great variation from the Cv!>mparatively simple iorm
found in the modern horsetail, but they are essentially of
the same type.

Flowering and flowerless plants. — Lotanists divide plants
into two great groups —flowering plants, which reproduce
themselves by means of pollen grains and ovules ; and
flowerless plants, which still retain the primitive marriage
customs of their ancestors. The flower is a comparatively
recent invention in the history of plant life, and its success
is shown by the dominant position in the jilant world which
the flowering plants now occupy. •

Many of the flowerless [ilants — like the horsetails— have
fallen behind their competitors. The ferns, in spite of their
conservatism, still hold their own, and seem in no danger
of extinction. Many other flowerless plants maintain thciir
position by sheer force of numbers. Yet others have be-
come completely* extinct, and can now be known only by
their fossil remains. But these latter are somelimes so
distinct that stems, ro(Rs, and spore boxes can be seen with
all their sharpness of outline unimiiaired ; the delicate
tracery of frond and leaf is visible, as clear and fresh as if
made yesterday. And such rocky herbaria tell us in un-
mistakable terms that our forest trees and other flowering
plants are after all mere parvenus and upstaits.

EXERCISES ON CHAPTER X.

1. Explain the furmaiion of iho scales whicli are fiet^utMitly seen

on the surface soil of a fernery. Whence do they arise? Whal liaj)])enb
to them if they are nliowed to grow? (King's Scliolaiship, 1902)

2. Point out the differences between the fronds of a fern and llie

leaves of most flowering plants. (1 901)

198 AN INTRODUCTION TO NATURE-STUDY

3. Show how the spore-prodiicin^^ plant of a fcrnjs attached to the
prothallus, and trace the early development of the former.

4. Make a list of the ferns, which you have seen throwing wild, and
state exactly in what kinds of places they were growing.

5. Make experiments to prove that the prothallus of a fern is capable
of manufacturing starch.

6. Make drawings of the spoie-bearing leaves of all the ferns you can
find, marking in each case the position of the spore-groups.

7. In what situations have you found horsetails growing? What
other plants were growing near‘d

8. What is the difference betw’ecn a seed and a spore ?

9. Describe the .situation in which the main stem of the bracken is
found, Its mode of growth, and the simpler facts of its structure. (1904)

10 . In W'hat respects do you consider the iliiz(nne of a fern (<7) similar ;

(/») dissimilar to the loot of a tree ? (Certificate, 1905)

11. Where aie the spores of a fern formed, and how are they

dispersed? Wliat do tliey produce on eeimination? (19C>5)

CHAPTER XI.

MOS.SES, MUSHROOMS, AND MOULDS.

40. LIVERWORTS AND TRUE MoSSES.

1. A common liverwort. — l.ook along the sides of a brook or
a well, and try to find a flat grreen plant with nuineioiis lobed
and ovei lapping branches. Jca( h branch is perhaps half an
inch across. This is one of the commonest liverworts (/V///Vz).
Notice the prominent midrib running along each liranch. In
spring, observ'C the ‘‘frilled” appearance of the end, caused by
the small new liranches.

Pull the plant up, and notice that it is attached to the soil by
a large number of fine Judrs which spring from the lower surface
of the midrib.

In Fel^ruary, or March, examine the upper surface of the
growing plant with a lens, and notice the small, dark-green balls,
mounted on short, thick stalks. Examine these at intervals
until May, and notice that the* stalks then grow rapidly until they
are two or three inches long Each is white, and still bears the
black ball (the capsule) on its summit. When the stalk is full-
grown, the capsule opens — its wall splitting into four parts — to
liberate the spores 1 low soon, after the liberation of the spores,
do the capsule and its stalk die down 1

2 . A common moss. - -Separate a single jdant Tom a tuft of
the common moss (/w/ua/irr) which grows, almost everywhere, on
the ground and on walls. Notice that the plant consists of a
stem perhaps half an inch high, thickly covered with small

200

AN INTRODUCTION TO NATURE-STUDY

simple j>rccn leaves. The moss is fixed in the Jjoil by a tuft of
fine hairs.

On some of thd plants notice a thin stalk (about half an inch
Joni^) sprin^dn^; from the top of the stem ; and on the end of the
stalk an ovoid capsa/e or spore-box. In cases vvhei e the stalk is
not yet full-^i'ovv n, notice tliat the capsule is covered by a conical
somewhat like a candle-extinguisher.

Select a plant bearing a ripe capsule, and warm it gently
before the fire — holding it over a sheet of paper — to dry it.
Examine the mouth of the capsule wath a lens, and try to see
the teeth whic h surround the opening. Then shake the capsule
ov(T moist soil in a small flower-pot to scatter the spores ; cover
with a sheet of glass and keep in a warm room. In a few days
notice that the,^ soil is covered v/ith fine green threads.
Ultimately new moss plants will grow from these.

The life-history of a liverwort. — One of the commonest
and simplest of this class of plants is known to botanists as
Pellia. It may generally be found growing by the sides of
streams or old wells. It has neither stem, leaves, nor root,
but consists of flat, green, overlapping lobes which fork at
their ends It branches very freely, and' in spring the new
brancdies give the ends of the lobes a frilled appearance.
A rather prominent midrib runs along each branch. The
plant is attached to the soil by a large number of fine hairs
which spring from the lower surface of the midrib.

'The whole appearance of this liverwort is very suggestive
of the prothallus (Fig. 147) of a fern ; and, indeed, it corre-
st)onds to a prothallus, not only in its general structure and
mode of life, but also m bearing sexual organs of a very
similar type. It was seen in ("hapter X. that a fern prothallus
at length produces an embryo, which grows up and forms the
spore-bearing generation which is what people usually under-
stand by a “ fern ”

The liverwort also gives rise to a spore-bearing generation,
but in this case it consists merely of a small, round, spore*

LIVERWORTS AND TRUE MOSSES

box, dark-grecA in colour, which is carried on the summit
of a white; stalk — the whole looking somewhat like a stout
pin. In Lebruary, or early Marc>\, the spdre-boxes may be
seen upon the upper surface of the plant as small balls,
perhaps one-sixteenth of an inch in diameter, protruding
from the mouth of a little pocket in which their early stages
are passed. About May, their stalks lengthen so rapidly
that in a few days the spore-boxes are lifted to a height of
two or three inches. Then each box opens by its wall
splitting into four, and the spores are liberated to germinate
and form new liverworts. Having thus shed the spores, the
box and stalk die down.

The complete life-cycle of a liverwort thhs includes two
unlike generations, as that of a fern does ; but it is a
different generation which attains the greater development
in the two cases. Tlie ordinary fern is the spore-bearing
generation ; the “ ordinary ” liverwort is the sexual genera-
tion, and its sporing off^5pring is not a separate plant at
all, but a mere stdlked box, almost entirely dependent upon
its parent.

The mosses. — A moss-plant appears at first sight to be
very similar in its general features to one of the higher
plants; for it has a little sUan, hiearing flattened green
leaves whicli build up carbonaceous food in the usual
way. It has no true roots, but fine hairs penetrate the
soil and d(i the work of roots by taking up solutions
of mineral food. It is all the more remarkable, therefore,
to find from its method of reproduction that the moss plant
belongs to the generation which conesponds to the
prothallus stage of a fern’s life-history, and not to the
leafy, sporing generation which it somewdiat resembles
superficially. •

The sexual organs of a moss are essentially of the same
type as those wdiich a prothallus bears, and here also the

202

AN INTRODUCTION TO NATURE-STUDY

tiny male cells gain access to the female celfc by swimming
through a drop of rain or dew. The result of fertilisation is

an ^tTibryo wliich, however, grows up
to form, not a plant with stem and
leaves, but a stalked sf)orc-case only.

In a tuft of the moss Funana^ which
is so common in all country places,
several stages of development of the
spore cases may usually be seen. Fig
1 56 re])resents a moss which is very
similar to luiJiaria but larger. In
the spore-case is still covered by a coni-
cal hood (r). In the stalk (.v) has
grown miK'b longer, and the hood has
dropped off 'The spore-f;asc or capsule
{/') is now seen to be a ])ear-shapcd
body, closed by the lid {d). When the
spoies are ripe, the lid becomes de

// 1 tached. The mouth* of the nodding

Ki(,. 156 —A Moss. W,
a plant witli s])nrc-caso still
covered by lioud (O('si).
/>’, a plant wntli ripe sy)oi
case Iji ) ; .V, stalk ; r/, Ir
r//, hails ( m). C, matu
spore-case with lid O) --
inovfxl ; /, fringe of teeth
(xj).

capsule is still blocked, however, by
a number of teeth (Fig. 156, C, p)
which remain clo.se together in damp
weather. In dry weather the teeth
separate, and allow the spores to fall
out. When a moss spore falls in a
favourable situation it germinates to
form a tine, branching network of
green threads, from which new moss-
plants arise as buds

The obvious ])lant of a moss like
that of a liverwort — therefore corre-

sponds to the prothallus generation of a ferri or horsetail.
Its sporing generation, corresiionding to the obvious fern-
plant or horsetail, is a stalked spore-case, which is always

THE COMMON MUSHROOM

203

more or less (dependent on its parent and dies down as
soon as it^j work of scattering the spores is accomplished.

41. THE COMMON MUSHROOM.

1. Habit of ^owth.- In what situations do yon find mush-
rooms grow'in<4 ? In what kinds of wenllun* and at what time of
the year aie llic}' most abundant Take iij) a miisliroom with a
trow'cl, and carefully wash di(^ caith fiom the lowxu' j^art to see
the tangle of white threads (called the inyccliuui)^ which is the
undcrgaoLind part of the plant. vSoe that several of these run
into the bottom of the stalk. On the underground mycelium
look for young mushrooms in the “ button ” stage. Look around,
and try to gml a series of mushrooms showing ail .stages from
the smallest buttons to fulh -opened spt'cimens.

2. Structure. - Dianv a side-view^ (natural size) of a full-
grown mushroom, showing the slixlk and tap. Running lound
the .stalk notice ,i ragged tkap, called the collar. What is tlie
height of the colUir from the base of the stalk? ICxamine
younger mushrooms to find what the collar leally is. Notice
that in young specimens a membrane or 7 'cil sti etches from the
edge of the cap to the stalk, and that as the mushroom grow's
larger this veil is torn away from the cap (Eig. 157), and icinains
as a ragged llap (tlic collai) on tlic stalk. In young specimens,
therefore, the lower side of the cap is <a)mpletely sliut in by the
veil, while in fully-grown ones it is exposed.

3. The gills and spores.— Cut the stalk acioss at tlic top, and
make a drawing of the low'cr surface of the caj). Notice the
radiating' vertical plates ftlic yx 7 /\), and their tlcsh coloured or
dark-browm tint. Be careful to show' the exact arrangement of
the gills in, say, a quarter of the drawing. Cut off the cap of a
mushroom which has blown gills and lay it, gills down, on a
sheet of paper ; cover it with a tumbler to slurdd it from
draughts, and ‘leave it for a day. Tlien take off the cap (buing
careful not to smear it along the paper), and observe the
radiating browm lines. On toucliing them, it will be seen that

204

AN INTRODUCTION TO NATURE-STUDY

the lines consist of fine brown dust. The particles of dust are
spores. They have evidently fallen from the gills.

4. The source of the mushroom’s food. —What is the colour of
the mushroom? Cut thfrough the stalk and cap in various
directions and notice the pure white “ flesh ” of the interior. Do
you think it likely that the plant can obtain carbonaceous food
from the air? Why not? Dry a mushroom and burn it care-
fully. Does it contain carbon ? Where must the carbon have
come from, if not from the air. Can you find any decaying
vegetable or animal matter in the soil in which mushrooms
grow ?

5. Toadstools. — Carefully compare the common mushroom
with other gilled fungi which look somewhat like it. Notice
particularly the following chatacters : the colour, shaj^e, and
texture of the surface of the cap ; the coloiii and arrangement of
the gills ; the pro])ortions of the length and thickness of the
stalk to the diameter of the cap ; the presence or absence of a
collar on the stalk ; the presence or absence of a cup, or scaly
swelling, at the base of the stalk.

'I'he following precautions are necessary in selecting mush-
rooms for food ; Never eat a “button” mushroom ; m this stage
wholesome and poisonous mushrooms cannot be properly
distinguished from each other. Reject all mushrooms which
show signs of a cup or a scaly swelling at the base of the stalk —
especially if they have also 'ivhitc spores and a collar.

The common meadow mushroom. — The common mush-
room (Fig. 157) may easily be found in meadow^s, especially
in autumn and after damp weather in summer The part
which rises above the surface of the ground consists of
a stout stalk, about three inches long and perhaps three-
(]uarters of an inch thick. On the upjier end of the stalk is
a ('ircular horizontal cap, convex and smooth above and
concave below ; with a ciiameter about equal to the length of
the stalk. The interior of the stalk and cap is composed of
a firm white fleshy substance. The underground part of the
plant consists of a tangle of fine white threads, most of

THE COMMON MUSHROOM

205

which are woven together into strands ; and it is easy to see
that several of these strands run into the base of the stalk.
Each of the fine threads is called n hypha, ztnd the network
which they together compose is known as the mycelium. It
has indeed been found by microscopic examination that
the whole plant is built up of such hyphae — closely packed
together in the stem and cap, more loosely aggregated in the
underground strands. The stalk of the full-grown mush-
room hears, a little above its middle, a ragged ring of tissue —
the collar, d'his ring is the remains of a membrane or veil
which in the younger stages reached
to the edge of the caj), completely
enclosing its lower surface ; but
which was torn off the cap (Eig. 157)
as the stalk of the “ button ” mush-
room elongated.

The reproduction of the mush-
room. — The lower side of the cap of
a mature mushrooMi bears a very large
number of radiating plates called the
giUs. These are at first pink, but
the colour afterwards changes to a
dark brown. Each gill i)r()duces an immense number of
extremely fine spores, too small to be seen individually by
the naked eye. When, however, the cap of a mushroom
is laid, gills down, on a sheet of paper and i)rotected fiom
draughts, a “spore print’' is obtained; the dust of the
fallen spores marks the positions of the gills in brown
radial lines. Quite recently it has been found possible to
raise new mushroom plants liy germinating the spores, and
there can be no doubt that this is the natural method of
reproduction. .

The method of life of the mushroom.— The mushroom,
like all the plants we have studied, thus consists of parts

Fill. 157. — Common Men-
dow Musbiooni. 'Fo the rij^ht,
mushroom in “button’' Mage

Qu-

206

AN INTRODUCTION TO NATURE-STUDY

which perform one or other of two duties ; 4 hat of feeding
the plant, and that of continuing the race. In this case the
food is supplied entireh by the underground mycelium ;
while the aerial part, consisting of stalk and cap, is concerned
only with the work .of scattering the sj^ores. There is
nothing corresponding to the leaf-green of the higher plants,
and the mushroom is therefore unalde to make use of the
carbon dioxide of the air (p. 34) as the source of the
carbonaceous food which is ne(“essary for its life. C"ar-
bonaccous and mineral food alike arc obtained from the soil
by the underground mycelium. T'he plant is, in short,
dependent upon carbonaceous food which has been
previously biiih up by some other plant or animal, and can
therefore grow only in soil containing decaying animal or
vegetable matter. It would be quite unable to subsist upon
the nutritive solution of salts wliicb was seen (p. 29) to
suffice (when supplemented by fresh air) for grc'cn j)lants.

Fungi. — 'The mushroom belongs to a class of plants called
the Fungi, all of which obtain their oarbonaceous food
ready-made from some other plant or animal, living or dead.
For this rc'ason many fungi are parasitic u])on other living
plants. Most of the diseases of crops and of forest trees are
due to fungi. 'The moulds which destroy food are fungi,
and the dry rot which ruins timber is caused by organisms
of the same class.

Toadstools. — The common meadow mushroom is a justly
esteemed article of food, but some other gilled fungi, which
are intensely poisonous, bear a suffic:iently close resemblance
to mushrooms to render them dangerous. The student
should therefore take every oj)portunity of examining these,
and of comparing them with the edible mushroom in the
manner described on p. 204.

MOULDS

207

42. MOULPS.

f. The growth of moulds. — Dapip three suiall slices of bread,
and cover then’i with tumblers to prevent them from drying.
I^^xpose one slice to ordinary daylight ; keep another in a daik
])lace at about the same temperature ; and submit the third to
the direct rays of bright sunlight as much as possible.

2. White mould (.l//oer). — In one 01 two days observe that
the bread is co\'ercd with white fleecy threads. Some of these
may grow to a height of an inch or more, and end in small black
knobs which can he seen with the naked eye. The knobs
contain spores. Examine the mould with the help of a lens.
On which of the three jiieces of bread is there most mould, and
on which the least ?

Mix freshly-l)oiled and strained juice of stewed fruit (preferably
colourless or nearly so) with an equal quantity of water. Half
fill a small glass with the mixture, and with the point of a needle
add a few spores from the mould on the bread. Cover the glass,
avoid shaking it, and examine day by day. Notice the delicate
threads {/lyp/nie) oi* the niyccJiuvi which spreads over the liquid
and sends down branches below the surface. Observe also the
hyphae which grow up into the air and bear spore-knobs at the
end. Similarly, sow some of the spores on a little of the nutritive
solution of salts (p. 27) contained in a clean glass. Do these
spores also develop into moulds? Why not?

Scratch through tlie skin of a njie fiuit {e.g. plum, apple,
grape, etc.) with a needle, and lay the fruit aside with the scratch
upward. Scratch a similar fruit m the same way, and rub into
the scratch a few mould-sjiores before laying it aside. With
these put a thiid fruit which has a perfectly wdiole skin. Com-
pare the fruits after a few days.

3. Blue mould {Pcnicillium ).— some days the white
mould on the bread will probably be crowded out by a blue or
greenish velvety mould called Pcnidlliufu. Examine it with a
lens. As with' Mucor^ make experiments as to the action of
light upon this mould ; the germination of its spores (which

2o8

AN INTRODUCTION TO NATURE-STUDY

form a greenish powder on the ends of the short aerial hyphae)
in fruit-juice ; and the action of the spores upon ripe fruits.

Common moulds. — In/the dust floating about in the air
the spores of certain moulds are almost always present.
When these spores fall upon materials which — like bread,
fruit, old leather, etc. — are capable of affording them
suitable food-substances, they germinate and form the
woolly growths which are familiar to everyone.

The white mould {Mucor ). — What is known familiarly as
white mould, and botanically as Mucor, is very convenient
for study on account of its abundance and large size. If a
piece of bread is kept in a damp atmosphere it generally
becomes covered, after a day or two, with a fleecy growth of
the white threads of this mould. These may attain a
height of an inch or more, and many of them bear at their
ends a small black knob, in which the spores are formed.
When mature, the knobs burst open, and the fine spores
are scattered in the air. The various parts of the mould are
best seen in position by scattering some of the spores, or a
little dust from a shelf, upon the surface of clear, colourless
fruit-juice in a glass vessel, and following the stages of
growth with a lens. It then becomes clear that the mould
— like the mushroom — consists of {a) a buried tangle or
mycelium of hyphal threads which take in the plant’s food,
and of {b) an aerial part which scatters the spores. The
mould also resembles the mushroom in not containing the
green colouring matter possessed by the higher plants, and
therefore in being dependent upon ready-made organic
food. Provided with this, it can grow freely even in the
dark.

Blue mould {PenidlHum ). — It is generally found that the
fleecy hyphae of Mucor ^ which first cover the damp bread,
are crowded out in a short time by the growth of another

BACTERIA

209

mould, which is known to botanists as Penicillium. This
also consists of a mycelium, which penetrates the nutritive
substance, and of aerial hyphae which produce spores.
Here, however, the spores are not borne in cases, but break
off from the ends of brush-like branches of the aerial hyphae
(PTg. 158)- The spores of Penicillmm are greenish-blue in
colour, and it is from this circumstance that the mould
receives its common name. The
colour is, however, quite different
from the leaf-green which gives the
higher plants the power, in sunlight,
of decomposing the carbon dioxide
of the air and building up their own
carbonaceous food — a power which
neither Penicillium nor any other
fungus possesses.

The smallest plants. — The de^
scription of microscopic organisms
is beyond the scope of this book,
but the student ought to realise that
by far the greater number of plants
are quite invisible to the naked eye.

Some of these — to be found in
every pond and ditch-are green, “

and, though they are of very simple

structure, they obtain their food in a manner substantially
resembling that adopted by a flowering-plant or a fern.
Others, like the yeast plant, are fungi, and are subject to
the limitations in food-supply which are characteristic of
that class. The smallest of all plants are the bacteria;
they are almost inconceivably minute, yet they possess an
influence upon^ the health and wellbeing of mankind which
it is impossible to over-estimate.

Fk;. xKZ.~--Prnicillium. An

N.S.

210

AN INTRODUCTION TO NATURE-STUDY

EXERCISES ON CHAPTER Xj.

1. Explain in what respects a moss plant resembles anci differs from
the prothallus of a fern. •

2. What structure in a moss corresponds, as regards reproduction, to
an ordinary fern plant ?

3. What do you mean by the term “ alternation of generations ” ?
Explain your answer by refei ences to ferns and mosses.

4. How docs a mushroom resemble and differ from a green plant in
its method of obtaining food ?

5. Why does a piece of damp bicad become mouldy when it is
exposed to the air ?

6. Describe simple experiments which prove that the dust of ordinary
air contains living particles.

7. Mention common plants which are wafted about by currents of air

in a dwelling-house, and jioint out changes which such ])lanls may set
up in articles of human food. (1905)

PART IL

ANIMAL LIFE

CHAPTER XII.

THE RABBIT: A TYJTCAL MAMMAL.

43. THE RABBIT: HABITS AND APPEARANCE.

I. The habits of the wild rabbit. — In what places have you
known wild ralj>bit.s to ha\ e a way'rcn ? In what kind of ground is
a rabbit warren gerwsrally found? How can you recognise it ? Are
all the holes of the warren of similar size, or can you distinguish
between main entrances and ‘H)olt-holes ”? Look for smooth
paths, perhaps nine inches wide, which lead to the main
entrances and intersect each other, so as to form “runs.” Watch
the animals feeding and playing ; to do this successfully it will
be necessary to keep very still and silent ; avoid walking on the
runs. What do the rabbits eat? Do they walk, or hop? How
do they run? Notice how conspicuous is the white tail of a
running rabbit. In June look for a nest of young rabbits. The
position of such a nest may often be recognisi'd, when the doe is
away from home, by a smooth patch of earth with which she has
covered up the hole. Dig up this very carefully and notice how
the nest is lined. Examine the young ones without hurting
them, and then cover them up again.

What is ihe*co/our of a wild rabbit ? Does the colour render
the animal less conspicuous? Are tame rabbits so often of this
colour ? Why not ? Watch a tame rabbit, noticing especially

212

AN INTRODUCTION TO NATURE-STUDY

the movements of its nostrils, whiskers, an(I, ears, and its
method of feeding. Try to see how it gnaws the bars of its
hutch, t ,

2. Fur. — Examine a dead rabbit. With what is the skin
covered ? What are the differences between the fur of a rabbit,
the hair of a dog, and the wool of a sheep ? Is fur curly ? Does
it lie flat on the skin ? Does it consist of different sizes of hair
— short, fine hairs and long, thicker ones ? What othei animals
do you know which have fur?

3. The head. — (a) The whiskers. — On what parts of the head
are the longest hairs found ? Dow do these differ, apart from
length, from ordinary hairs ? What other common animals have
whiskers ? Do such animals often make their way through
narrow passage^? What do you suppose is the use of the
whiskers?

{b) The skull. —Feel the bones of the head through the skin,
and make out the rounded brain-case, the ridge above and the
arch below each eye, and the positions of the jaws.

{c) The c.xternal ears. — Examine the large ear-flaps. Notice
that the upper parts are thin and almost transparent, and that
the lower parts are gristly and lead into the interior of the
head.

{d) The eyes. — Notice that the eyes are at the sides of the
head. Is this position an advantage to the rabbit? Examine,
in each eye, the upper and lower lids ; and also, in the angle
of the eye next the nose, the third eyelid—'n fold of white
skin. Take hold of this fold with the forceps and see that it
is easily pulled over the eyeball. Look in a mirror and see
the little fleshy body which occupies a similar position in your
own eye ; this corresponds to the rabbit’s third eyelid. In the
visible part of the rabbit’s eyeball notice the round dark pupil
in the middle (contrast the pupil of a cat’s eye) ; the coloured
ring (the irLi) surrounding the pupil ; and the “ white ” (called
the sclerotic) surrounding the iris.

{e) The lips and nostrils.— how the upper lip is split
in the middle line, so as to show the front teeth.’ What is the
use of the split ? Notice the grooves passing from the upper lip
to the nostrils.

THE RABBIT

213

(/) The inside of the mouth, — Open the rabbit’s mouth and
notice :

(i) The two gnawing or incisor t^eth in th^ lower jaw, and
the pair of strongly-grooved incisors*which are so conspicuous
in the upper jaw. Just behind the large, upper incisors two
smaller incisors may be felt with the finger. Separated by a
wide space from the incisors are \\\q. grinding teeth — six on each
side in the upper jaw, and five on each side in the lower jaw.

(ii) The tongue^ lying between the halves of the lower jaw.

(iii) The hard ridges running across the fore half of the roof
of the mouth.

(iv) The hairiness of the inside of each cheek, between the
incisor and grinding teeth.

4. The neck. — Notice how the neck enables the head to be
turned freely in various directions without the bod> being
moved. Feel through the skin and identify :

(a) In front of the neck, the trachea or windpi])e, with the
or “ voice box” at its upper end between the halves of
the lower jaw.

{b) The bones of the neck-part of the spine,

5. The trunk. — Fe,el through the skin and make out the spine,,
the breast-bone^ and the curved ribs which connect these. The
spine, breast-lwne, and ribs together form a bony cage which
encloses the fore-part (the thorax^ of the body. The hinder
and larger part of the body (the abdojne?i) is not protected by
ribs, but the bones of the spine are largest and stoutest in this
part of the body.

6. The limbs. — How many limbs has the rabbit ? Which pair
is the longer? Is the difference in length an assistance in
leaping? Make out the main divisions of each limb, and, by
feeling through the skin, the manner of attachment of its bones
to the bones of the body (Fig. 161).

7. The tail. — Notice the length, shape, position, and colour of
the tail. The chain of bones inside it is a prolongation of the
spine.

Methods of studying animals. — In studying animals,
methods similar in principle to those described in previous

214

AN INTRODUCTION TO NATURE-STUDY

chapters for plants should be employed. A-real knowledge
of the habits of animals can only be obtained by watching
them as closely rs possible in their natural surroundings. It
is often very difficult to get sufficiently close to shy animals
to see them distinctly without causing alarm, and a good
field-glass is a valuable help in such cases. A great deal
of first-hand knowledge of wild life can, however, be gained
without such aids if the student will learn to move quietly
and silently, and to remain motionless as soon as he is in a
good position for observation. "I'he books of such masters
of woodcraft as Richard Jefferies, William J. Long, Ernest
Thompson Seton, and W. IT. Lludsoji give charming
descriptions ofr the methods of tracking and studying
wild animals, and should be carefully read by every field-
naturalist. Observations made in the field should be at
once recorded, with the date, in a note book.

Many animals can be kept for some time, without cruelty,
in confinement ; and a more intimate knowledge of certain
of their habits can l)e thus obtained The practice of keep-
ing pets is, however, to be encouraged only when every
possible care is taken to secure the comfort of the captives.

To understand the internal structure of an animal,
dissection is necessary. This consists in exposing and
separating the internal organs of the dead animal from each
other, in order to notice their mutual relation. A careful
outline drawing of every dissection should he made and
preserved. The student should make it a rule never to kill
any animal unless for some useful purpose, and then to do
so in the quickest and most painless manner.

The habits of the rabbit. — Wild rabbits live in burrows or
underground passages which they excavate, by means of
their strong feet, in the soil of sandbanks,, fields, woods,
etc. The animals are sociable, and the burrows belonging
to any one community are collectively known as a warren.

THE RABBIT

215

The passages the warren communicate with the outside
world by rneans of openings, some of which are in common
use, while others seem to be used Inainly as^ “ bolt-holes ” in
cases of sudden alarm. A rabbit which is bolting to its
burrow exposes the white underside of its tail, and thus acts
as a danger signal and guide to its fellows. When a rabbit
is startled, or puzzled by seeing some unusual object, it

Fi<j. 159 — Rabbits.

generally thumps the ground smartly with its long hind-
foot ; other rabbits in the neighbourhood are therel^y
warned.

It is common to find, outside a rabbit warren, a number
of intersecting paths, ])erhaps nine inches wide, and worn
smooth by the patter of little feet. These are the highways,
or “runs,” which lead from the holes of the warren to the
various feeding-ground.s.

Rabbits breed very rapidly ; it has been estimated that in
five years a single pair might have about a million descen-
dants, were it not for the countless mishaps to which rabbits
are exposed. The young are born and suckled in a special

216

AN INTRODUCTION TO NATURE-STUDY

shallow burrow, which the doe excavates ancj lines with dry
leaves, fur, etc. When she leaves the nest for any purpose
she covers up thr entrance with soil.

The proportions of the parts of the body of a very young
rabbit are markedly different from those of the adult. The
head is relatively larger, the tail longer, and the ears shorter;
while the hind limbs and fore limbs are of almost equal length.
During the first six months of its life the animal gradually
takes on the proportions of the adult — with small head, long
ears, large hind legs with long feet, and small, upwardly^
turned tail.

A rabbit is able to stand upright on its hind legs, and to
maintain itself In this position for a considerable time. It
thus obtains a wider view and a greater choice of food.

The great difference in the length of the fore and hind
legs gives the animal a characteristic gait. “In a freely
moving rabbit,” says Jefferies, “both fore-feet stop when the
hinder come up — one hinder foot slightly behind the other,

' and rather wide apart.” Rabbits are exclusively vegetarian
feeders, living on green herbs and on the tender shoots and
bark of shrubs and young trees.

The external characters of the rabbit. — The outside of
the rabbit’s body is almost entirely covered with fur. This
consists of two kinds of hair — coarse and fine. The coarser
hairs are fewer in number and longer than the fine ones,
which they protect from wet. The fine hairs are extremely
closely-set, and stand straight out from the skin. In a seal-
skin coat only the short hairs of the fur are to be found ;
the longer hairs have been removed by the dressing process.
The great warmth of furs is due to the air which is entangled
between the fine, close hairs. It is generally the case that
fur-bearing animals are exposed to either mud or wet by
their method of life ; in spite of this fact, while the hair of a
dog soon becomes wetted by rain, and the wool of a sheep

THE RABBIT

217

retains a great*, deal of dirt, furred animals are noted for
keeping their coats clean and dry.

The longest hairs of the rabbit a*j;e tire sti/f whiskers which
stand out from the upper lip, the cheeks, and above the
eyes. They are extremely sensitive to touch, and are of
great assistance to the animal in finding its way through the
dark burrows.

The colour of the wild rabbit is greyish brown, except on
the belly and undcT the tail, where it is white. This colour
harmonises well with the surroundings, and renders the
animal much less noticeable. Wild rabbits are exposed
to so many enemies, that individuals whic h happen to be
born with conspicuously coloured fur hav^ generally but
a poor chance of surviving and leaving offspring to inherit
their disadvantages. There is thus in each generation a
natural selection of the animals which are best protected,
by their colour, from observation. Among tame rabbits,
on the other hand, protective colouration is of very little
importance, and bne variation of colour is as likely as
another to be transmitted by heredity to the next generation.

The regions of the body.- -For convenience and prec ision
in describing animals it is customary to use the words
anterior and posterior to indicate the fore, or head, end, and
the hind, or tail, end respectively. The belly-surface is said
to be ventral, and the back dorsal.

The body of a rabbit obviously consists of head, trunk,
a short tail, and four limbs. The general arrangement of
the bony framework, or skeleton, (Fig. 161) which supports
the softer parts may be felt through the skin. The skeleton
consists of (1) the skull \ (2) the spine or vertebral cohtmn
(generally spoken of as the back-bone), placed dorsally, and
reaching from the anterior end of the neck into the tail ;
(3) the ventral sternum or breast-bone, which is connected
with the vertebral column by means of curved ribs ; (4) the

2i8 an introduction TO NATURE-STUDY

bones of the two pairs of limbs, with the shcjulder- and hip-
bones to which they are attached. The bones will be
studied in more »1etail in^the next chapter.

The trunk is divided into two regions — an anterior thorax,
or chest, (enclosed in the bony cage formed by the ribs,
sternum, and the adjoining part of the vertebral column),
and a posterior abdomen. The two cavities are divided from
each other by a fleshy partition called the diaphragm.

Organs of special sense. — In addition to the sense of
touch which is possessed by the whole surface of the body,
the rabbit has organs which enable it to distinguish objects
by sight, sounds, scents, and taste. Its sense of smell is so
keen that, to be^^successful in snaring rabbits, “ in walking to
the spot selected for the snare it is best to avoid even step-
ping on the run, and while setting it up to stand back as far
as convenient and lean forward. The grass that growls near
must not he touched by the hand, which seems to impart
a very strong scent. The stick that has been carried in the
hand must not be allowed to fall across The run ; and be
careful that your handkerchief does not drop out of your
pocket on or near it. If a bunch of grass grows very tall
and requires parting, part it with the end (not the handle)
of your stick.” ^

The shape of the ear-flaps, which can be turned in
different directions (PTg. 159), enables the rabbit to catch
very slight sounds.

The eyes are placed on the sides of the head, so that the
animal has a wide field of view, and an enemy approaching
from behind is not likely to be unnoticed. The eye of
the rabbit is very similar in structure to our own, but it
possesses one useful adjunct which ours has lost, in the
shape of a third eyelid—dLXi opaque flap of skin which lies in
the inner angle, and can be drawn over the eyeball at will.

^Jefferies, The Amateur Poacher (Smith, Elder & Co.).

THE RABBIT

219

little flesh); nodule in the corresponding position of the
human eye is a*rudiment of a similar structure.

The rabbit a gnawing animal. — Rabbits are much
addicted to gnawing young trees fbr the sake of the bark
and the softer juicy tissues between bark and wood.
Even tame rabbits exhibit the same instinct by gnawing
their wooden hutches, although these are of no use
as food The gnawing is done by the sharp teeth, called
incisors, which are conspicuous in the middle of both upper
and lower jaw. In the upper jaw two incisors (which are
so deeply grooved that they look like four) are visible even
when the mouth is closed, owing to the split in the middle
of the upper lip. The hardest part of the toyth (a substance
called mamd) is at the front. Behind this the tooth is
composed of a softer, bony material called de^iiuie ; and the
back of the tooth consists of still softer dentine. The result
of these differences in the comj)osition of the various parts
of the tooth is that the gnawing of hard substances wears
away the back of the tooth most, the middle part next, and
the front least of all ; and thus a sharp chisel-edge is always
maintained Moreover, the teeth of the rabbit never stop
groiving^ so that they never become aj)preciably shorter
through use. Immediately behind the tw^o visible incisors
of the upper jaw, another and smaller pair can be felt by
the finger ; the enamel-faces of these are directed back-
wards towards the cavity of the mouth. The softer and
more easily worn faces of the two pairs of upper incisors are
thus in contact, and are continually worn down to form a
groove. Into this groove the two incisors of the lower jaw
bite. The incisor teeth stand well out from the jaws, and
the split upper lip can be drawn back, so that the lips are
not injured by gnawing. In the hinder part of the mouth,
where the chewing, or mastication, of the food takes place, are
six flatter but cross ridged grinding teeth on each side of the

220 AN INTRODUCTION TO NATURE-STUDY

upper jaw, and five on each side of the Ipwer jaw. The
insides of the cheeks are protected from sharp splinters of
wood by a patc^h of hair^on each side, which ex'cends from
the region of the inciflors to the grinding teeth behind.
The roof of the mouth is protected by hard cross-ridges,
and the tongue by tough skin.

Eodents. — Rabbits and hares, rats and mice, and squirrels
are said to be rodents (Lat. rodo, J gnaw), as they not only
agree in the gnawing habit, but also in other very important
respects.

Mammals. — Rodents, and all other animals which suckle
their young, are included by naturalists in the class Mam-
malia. These ^ animals agree further in breathing air, in
having warm blood, ai>d in being more or less completely
covered with hair.

Vertebrates. — Mammals, birds, reptiles, amphibians, and
fishes are grouped together to form the sub-kingdom Verte-
brata. They are given this name because they all possess a
spinal, or vertebral, column (which usually consists largely of
a chain of bones), running below the dorsal surface (p. 217)
of the body, from neck to tail.

The position of the rabbit in the animal kingdom. — It is
clear from the above that the rabbit is, in the first place, a
vertebrate animal ; it belongs, secondly, to the 77 ianimalian
class of vertebrates, and thirdly, to the rodent-oxd&c of
mammals.

EXERCISES ON CHAPTER XII.

1. In what respects does the hind-fotH of a rabbit differ from the fore-
foot ? What is the use of the difference ?

2. Describe the way in which a rabbit runs. What precautions does

it take when feeding in an open place ? • (1901)

3. Make observations of the habits and external characters of hares,
and compare them, point for point, with those of rabbits.

THE RABBIT

221

4. De«:cnbe the ijiside of a rabbit’s mouth, and explain the advantage?
of any*peculiar features to be seen in it.

5. Mention the two chief constituents o? a rabbit’sy tooth. Describe
by what means the edges of a rabbit’s incisor teeth are kept sharp.

6. Make a list of all the vertebrate animals with which you are
acquainted. Why are they called vertebrates ?

7. By what external characters would you recognise that an animal
was a mammal ?

CHAPTER XIIT.

HOW A RABBIT LIVES.

44. THE SKELETON AND MUSCLES

•

1. The examination of the bones. — In a boiled rabbit clear away
the flesh from the bones. Before separating a bone, notice
carefully how it is attached to neighbouring bones. Notice
also, especially in the limbs, the attachment of the bundles of
flesh {^n?/sc/es) to the bones, the ends of each muscle being
fixed to separate bones. Notice that the places of attachment
of the largest muscles are marked by ri(Jgcs or roughnesses
on the bones.

2. The skull. — Observe the two rounded knobs at the back
of the skull, which fit into hollows on the first bone (vertebra)
of the vertebral column. In the skull notice the saw-like
boundaries of the various bones, and make out : the great,
rounded brain-case ; the external openings of the cars ; the eye-
sockets ; the snout, with the two nasal chambers ; and the upper
and lower jaws. Before separating the lower jaw observe care-
fully how it is hinged on the arches which run below the eyes,
and notice the great muscle on each side which moves it.
Examine the teeth in detail, and remove them one by one from
their sockets Notice the bony shelf or palate separating the
nasal chambers from the cavity of the mouth. Draw a side
view of the skull.

Shave off the top of the brain-case with a sharp knife, and
examine the brain.

3. The vertebral column. — Make out that each of the bones

THE RABBIT: SKELETON AND MUSCLES

223

(vertebrae) which compose the vertebral column is really a ring,
and that the whole column is therefore a bony tube. In this
tube is enclosed the spinal cord, a backward continuation of the
brain. Examine and draw vcrtebrag from tl/e various parts of
the column, and notice how they vary in shape and size.
Compare vertebrae from («) the neck, {^) the region of the chest
(notice the attachment of the ribs), (r) the abdominal region, (<^/)
the region of the hips (four united vertebrae ; leave these for the
present in position between the hip-bones), (c) the tail.

4. The ribs and sternum.— Examine the manner of attachment
of the anterior (p. 217) pairs of ribs to the sternum or breast-
bone. Some of the more posterior ribs are free at their ventral
ends.

5. The bones of the fore-limb. — Examine the bones in order and
make out : (a) the triangular shoulder-blade, {^) the single long
bone of the upper arm (its upper, rounded end fitting into a
socket in the shoulder-blade ; its lower end forming, with the
bones of the fore-arm, the elbow joint), (c) the two bones of the
fore-arm (these lie side by side ; notice the peg which makes it
impossible for the hinged elbow -joint to be bent back beyond a
straight line), {d) the small bones of the wrist, (e) the bones of
the hand.

6. The bones of the hind-limb. — Notice that the limb as a whole

is divided into parts— upper leg, leg, ankle and foot — which
correspond to the divisions of the fore-limb. Make out : {a)
that as the bone of the upper arm fits into a socket in the
shoulder-blade, so the bone of the upper leg has a ball-shaped
end which works in a socket of the hip-bone. Notice that the two
hip-bones are joined together ventrally, and that they are fixed to
the welded vertebrae of the hip-region. Does this give increased
strength to the hind-limb ? Identify : the two bones of the

leg (between knee and ankle) and notice that they differ from
the corresponding bones of the aim in being fused together in
the lower part ; (c) the bones of the ankle, and (d) the bones of
the foot.

7. The struct\u:e of a long bone. — Take the long bones of the
upper arms and upper legs, and examine them further. Bieak
one across the middle Is it solid or hollow ? What is the

224

AN INTRODUCTION TO NATURE-STUDY

advantage of its being hollow ? Is the tube empty or does it
contain marrow ? Are the ends of the bone hollow or solid ?
Place one of the bones on a bright hot fire. Is thet*e any sign
of burning ? Do 's all the bone burn away ? Carefully remove
Avhat is left, and compare the brittleness of the “ burnt ” bone
with that of an unburnt bone. Place another bone for several
days in a cupful of water to which has been added about two
teaspoonfuls of strong hydrochloric acid. Then take it out, wash
it, and try to bend it. Continue the treatment until the bone is
soft enough to tie in a knot. Can you tie an ordinary bone in a
knot? Why not? I'ut a burnt” bone in similar dilute acid.
Does it dissolve ? What do you think gives a bone its hardness ?

8. Bones moved By muscle. — Stretch out one of your arms and
grasp the middle of the upper arm firmly with the other hand.
Now bend the elbow, and notice that the great muscle (the
biceps) of the front of the upper arm thickens and becomes
shorter. Straighten the arm again, and notice that the muscle
becomes thinner and longer again. Examine Fig. 160, which
shows how the upper end of the biceps is attached at a to
the shoulder-blade and its lower end to one of the bones of the
fore- arm at P, If the biceps muscle shortens, the fore-arm must
be pulled up, because the shoulder remains stationary.

Carefully notice the various movements of which your arm is
capable — e.g. extension of the arm ; bending (flexure) on the
elbow-joint ; rotation of the fore-arm, so that either the palm or
the back of the hand can be turned upwards ; and grasping.
Observe your power of touching the tip of the little finger with
that of the thumb. If a human skeleton is accessible watch how
one (which ?) of the two long bones of the fore-arm rotates when
the hand is turned over. How many of these movements can
the rabbit make ?

The uses of the skeleton.— The bodies of vertebrate
animals (p. 220) are supported, and their more delicate parts
protected from injury, by an internal framework called the
skeleton. In some of the simpler fishes this is composed
of gristle or “ cartilage ” ; but in more highly developed
animals it consists almost entirely, in the adult state, of

THE RABBIT: SKELETON AND MUSCLES

225

bone. Further^ almost all the bones are connected with
strands or bur/dles of red flesh called muscle, which the
animal is able to shorten or “coptradt’’ at will. When a
muscle shortens, the bones to whieh its erfUs are fixed are
of necessity pulled nearer to each other. If the bone at
one end of the muscle remains stationary, that at the other
end is moved into a new position. This is, generally
speaking, the manner in which the numberless movements
of the limbs, head, etc., are made.

Fig. 160. — The .action of the Biceps muscle, a, the attachment of the
muscle to the shoulder-blade ; attachment of the muscle to the fore-
arm ; elbow ; iV^ hand.

The movements of the limbs. — An excellent illustration
of this relation between the bones and mu.^^cles is seen in
the bending of the arm at the elbow. When the arm is
bent, a great mass of flesh, the biceps muscle, in front of
the upper arm may be observed to become much thicker.
The muscle (Fig. 160) thickems because it becomes shorter.
Its upper end is attached to the corner of the shoulder-
blade (<2), which remains stationary ; while its lower end is
connected at i^with one of the bones of the fore arm. The
shortening of the muscle therefore draws up the fore-arm.

N.S. P

226

AN INTRODUCTION TO NATURE-STUDY

The elbow-jointy about which the motion Jakes place, is a
very perfect hinge. Several other forms df joint are also
found in various parts j>f the body. It is seeif, when the
skeleton is exaAiined, t 4 iat in every case the characters of
the joints and the attachment of the muscles are most
admirably adapted to the movements with which they are
associated.

The study of the skeleton — The study of the rabbit’s
skeleton is not only highly interesting in itself, but necessary
for the intelligent appreciation of the animal’s life. And
when it is compared with the skeletons of other familiar
animals, a common plan of structure is found which illus-
trates in the most convincing manner the kinship which
often exists between very dissimilar creatures. Such a
comparison shows that, almost bone for bone, the skeleton
of a rabbit corresponds with that of a man or a horse, and
even with that of a bird or a frog. Mounted skeletons are
shown in most natural-history museums, and the student
should, whenever possible, examine and compare them.^ He
can himself, however, easily separate the bones from a boiled
rabbit, and make out their main features and relationships.

The rabbit’s skull and backbone — The bones of the
head are collectively known as the skull. 'This consists of
(i) a large brain case; (2) the cavities for the organs of
special sense, viz., (a) a pair of nasal chambers (in which
the organ of smell is located) in front : their hinder ends
open into the top of the throat ; (^) the eye-sockets at the
sides, and (c) the flask-shaped chambers for the internal ears
at the sides of the hinder end of the brain-case ; (3) the
jaws : the upper jaw is rigidly attached to the brain-case,
but the lower jaw is hinged at each side on the hinder end
of the bony arch which runs below the eye. Both upper
and lower jaws bear teeth, which are fixed in sockets. On
^See foot-note, p. 231.

Fic, i6i. — The Rabbit. The skeleton in position, seen from the left
side.

the exception of the first and second, all the vertebrae are
formed on essentially similar lines, there is considerable
variation in shape and size in the different regions of the
spine, as may be seen from Fig. i 6 i. There are seven neck
vertebrae, and this number is remarkably constant in
mammals (p. 220). Following these are the chest vertebrae,
which bear pairs of ribs. The majority of the libs curve
round and join on to a ventral bar of bone called the
sternum or breast bone ; so that the cavity of the chest,
containing those very important organs the heart and lungs,

228 AN INTRODUCTION TO NATURE-STUDY

is enclosed in a protective bony cage. The^vertebrae of the
abdominal region of the body are very large and stout.
Between them s^nd the ;;ail-bones are four fused vertebrae,
forming a mass which on each side gives attachment to the
large hip-bone.

The bones of the rabbit’s limbs.— The fore and hind-
limbs of the rabbit are obviously comparable : the upper
arm corresponding to the upper leg, the elbow to the knee,
the fore-arm to the “leg,” the wrist to the ankle, and the
fore-foot to the hind-foot. This similarity becomes even
more apparent when the limb-skeletons are examined.
Commencing in each limb at the end nearest the body we
find a single 'long bone. In the fore limb the rounded,
upper end of this bone works in a socket at the anterior
angle of the shoulder-blade, a triangular plate on each side
which overlies the chest dorsally ; in the hind-limb the
rounded end of the corresponding bone works in a cup in
the hip-bone. Again, between the elbow and the wrist are
two bones lying side by side ; and between the knee and
the ankle are two corresponding bones, although here they
are only separate in their upper parts. Similarly, the
wrist bones correspond to the ankle hones, and the bones of
what may be called the fingers to those of the toes. Certain
of the ankle bones are, however, much elongated : obviously
a great advantage to an animal which progresses by a series
of hops—owing to the increased leverage which is thereby
given to the hind-foot. The rabbit’s fore-foot bears five
toes, the hind-foot four.

The structure of a long bone. — The long bones of the
limbs are hollow except at the ends. Strength and lightness
are thus secured by a device (the hollow cylinder), which
has already (p. 72) been seen to be adopted by the
supporting structures of plants, and is also copied by
human engineers. The cavity of the tube is filled by

THE RABBIT; DIGESTION

229

marrow, which .supplies the bone with food. The hard,
bony tube itself is partly composed of mineral matter and
partly of animal matter. The miperal matter is left as a
white, brittle framework when the 'animal /matter is burnt
away; while on the other hand the mineral part — which
gives the bone its rigidity — may be dissolved out by
immersing the bone in dilute hydrochloric acid, leaving the
organic tissue as a soft flexible substance having the shape
of the original bone.

45. HOW THE RABBIT DIGESTS ITS FOOD.

I. A solution of starcli will not pass through a thin membrane.—

Rub up with water as much starch as will lie orFa shilling, so as

to form a thin “ cream,” and then pour
on it about a cupful of boiling water.
The starch swells up and largely dis-
solves in the water. Add a few drops
of the starch solution to about half a
pint of water, stir, and test it by adding
a little iodine solution (p. 2, foot-note). A
beautiful blue colour is obtained, show-
ing that the test is a very delicate one.
Now take a thistle funnel and with a file
cut through the stem about six inches
below the head. Wet a piece of parch-
ment paper or thin bladder (having
previously held it up to the light to be
sure there are no holes in it), and tie it

tightly across the mouth of the funnel.
Fill the head and about an inch of the
stem with the starch solution. This can
easily be done by means of a “ canula,”
such as is used for filling fountain pens.
Now put the .funnel into a beaker of

Fro. 162.-— Expetiment to
show that sturcii solution
will not pass through a thin
nifi.hjrano. b, beakt-r ; w,
water; parchmeit

papei ; stem of thistle

itinnel ; .v, starch solution in
head of thistle funnel.

water, in the manner shown in Fig. 162, and put the arrange-

ment aside for a few hours. After that time add iodine solution

230

AN INTRODUCTION TO NATURE-STUDY

to the water in the beaker. No blue colour is formed, showing
that no starch has passed through the membra'ne.

2. A solution of sugar will pass through a thin membrane. —A
delicate test for ^certain yarieties of sugar (not, however, table

•sugar) is a liquid known as Fehlmg’s solution.^ Place a
particle of honey in a test tube with a teaspoonful of f'ehling’s
solution, and put the test tube into a vessel of boiling water.
Notice that in a short time the blue colour of the solution dis-
appears and the liquid becomes red and turbid.

Now repeat Experiment 46, i, but instead of starch solution
use honey dissolved in water. To show that some of the honey-
sugar has passed through the membrane, take about a teaspoon-
ful of the water in the beaker, and put it in a test tube with
twice as much Fehling’s solution. Heat as before, and notice
the red turbidity. If table sugar is used it may be recognised by
the sweet taste of the water after the experiment.

3. The action of saliva on starch. — (a) Chew a piece of india-
rubber to induce a free flow of saliva, and collect the liquid. In
one test tube put half a tcaspoonful of starch solution ; in a
second tube put a mixture of equal quantities of starch solution
and saliva ; in a third put saliva alone. Keep the tubes at
blood heat for twenty minutes. Then add a little water to
each tube and divide its contents into Dvo parts, 'best one part
of each for starch with iodine solution, and the other part for
sugar with Fehling's solution. The first tube contains only starch.
The second now contains no starch, but shows the presence of
sugar. The third contains neither starch nor sugar. Evidently
the saliva has changed the starch of the second tube into sugar.

id) Repeat the experiment, but keep the mixture of starch and
saliva in a cold place. No sugar is produced.

The necessity for food.— It is common knowledge that a
rabbit, like every other animal, must have a regular supply

1 Prepared by adding to a solution of copper sulphate first tartaric
acid, and then caustic soda until the blue mixture is clear. It may be
obtained from a chemist if the materials are not available.

THE RABBIT: DIGESTION

231

of food if it is to continue healthy, and that it would soon
die outright if food were withheld. The reason for this is
that the living substance of the anitnal’s body is incessantly
wasting away. The rabbit cannot move a muscle except at
the expense of the living substance of the muscle, and the
more active is its life, the more rapidly does its body waste.
It is to counteract this continual waste by continual forma-
tion of new living substance that food is taken.

But the succulent plants wBich the rabbit eats are not
suddenly transformed into animal muscle and bone, and so
forth, when they are swallowed. They have first of all to
undergo a process which is called digestion. This takes
place in a tube — the digestive canal — which*runs from end
to end of the body. 'Fhe digestive canal of the rabbit is
coiled in a somewhat intricate manner. That of the frog is,
however, much simpler and more typical of vertebrates (p.
220) generally, and will serve equally well in so elementary
a consideration of digestion as the present.^

The frog’s digestive canal. — The hinder end of the frog’s
mouth opens (Fig. 163) into the gullet a short wide

tube which leads to a capacious bag called the stomach (st.).
The termination of this is continuous with a coiled narrow
tube called the small intestine {s. in.), which passes suddenly
into a much wider large intestine or rectum. I'he rectum
opens to the exterior, at the hinder end of the body, by
an aperture (a?L) known as the anus. In addition to the

^Note to Teachers. — A general dissection of a frog should be
made and exhibited to the class. Detailed instructions for such a dis-
section will be found in Marshall’s The Frog (SmlLh, Elder & Co.) or
in Huxley and Martin’s Elementary Practical Biology (Macmillan).
The frog’s heart continues to beat for some time after the death of the
animal, and may be shown as an illustration of the next section of this
chapter. Teachers who are unskilled in dissection may obtain prepared
dissections, mounted skeletons, etc., from Newmann & Co., 84 New-
man Street, London, W.

232 AN INTRODUCTION TO NATURE-STUDY

digestive tube proper, two large digestive glands, the liver
and the pancreas, should be carefully noticed. The liver
(Ir.) is a large, (^rk red drgan, consisting of two lobes which
lie at the sides of the stomach. It makes a digestive fluid
called bile. The pancreas {pn.) is an elongated body which
lies in the loop between the stomach and the first portion — >
called the duodenum (du.) - of the small intestine. It makes
a digestive fluid called the pancreatic juice. In the frog both

Fig. 163.— The Frog, di'isccted from the left .side, gul, gullet; sty
stomach; du, duodenum; s. tut, small intestine; an, anus; Ir, liver;
pity pancreas; b.d, bile duct; bl^ urinary bladder; c.art, i.au, s v, Vy
parrs of the heart; cn. 3, “body” of 3UI vertebra; cus t, Eustachian
tube ; gly glottjs, leading to left lung, and r.lns:^ right lung ;

n.(i, I, arch of ist vertebra; p.na, internal opening of nostiil; sp.cdy
spinal cord ; i>pL spleen; tngy tongue; kd, kidney; ttr, ureter; z>o,ty
vomerine teeth.

the bile and the pancreatic juice are discharged into the
duodenum by one tube or duct (b.d.). Small digestive
glands also occur in the inner wall of the stomach ; these
discharge a fluid called gastric juice into the cavity of the
stomach.

The rabbit’s digestive canal — In its main features the
digestive canal of the rabbit resembles that of the frog;
here also the mouth opens into a long tube consisting of
gullet, a bag-like stomach, a small intestine, and a large

THE RABBIT: DIGESTION

233

intestine. There are also a liver and a pancreas which dis-
charge their fluids- -by separate ducts, however, — into the
first part of the small intestine; and the stomach is supplied
with gastric juice by small glands m its ir^er wall. There
are, however, certain differences besides those of size in the
digestive tubes of the two animals. In the first place, a
fluid called saliva is poured into the rabbit’s mouth by the
ducts of salivary glands which occur near the mouth.
Secondly, the coils of the small intestine are very much
more complicated than in the frog. And lastly, at the
junction of small and large intestines there is given off, in
the rabbit and in herbivorous mammals generally (when
these have simple stomachs, — p. 261), \ great, spirally-
constricted tube which ends blindly in a finger-like process.

How the rabbit digests its food. — A rabbit needs food to
repair the constant waste of substance which the activities of
its life entail ; and the same is true of every other living
thing, be it plant or animal. Now, every part of a rabbit s
body is irrigated ^and drained by the finest branches of a
system of pi[)es through which blood is always flowing ; and
it is in this blood-stream that the food is conveyed to the
muscles and other organs which are to be repaired. The
food finds its way into the blood when that fluid is flowing
through the small vessels which lie in the thickness of the
wall of the digestive tube. Before food can gain access to
the blood it must be in a condition in which it is capable of
diffusing through the thin membrane which separates them.
Digestion is the process which renders food soluble and diffusible,
and hence capable of passing into the blocni. The food of
animals is of several diflerent kinds. A few of these are
soluble and diffusible at the time they are eaten, but most
of them are rjeither, and therefore require treating according
to their nature. This is why so many different fluids are
poured into the rabbit’s digestive canal. Saliva, gastric

234

AN INTRODUCTION TO NATURE STUDY

juice, bile, and pancreatic juice are each capable of acting
upon certain constituents of the food and rendering them
soluble and diffusible.

It would be beyond the scope of this book to consider
the work of these fluids in detail, but the action of saliva is
not only fairly typical, but it can easily be imitated outside
the body. Starch is a very common constituent of vege-
table foods, and its presence or absence is readily determined
by the blue colour which it gives with a solution of iodine.
Starch is (juite insoluble in cold water, but when treated
with hot water it swells up and, to a great extent, dissolves,
hut a mere solution of starch cannot get into the blood,
for it is incapable (Exjit. 45, i) of passing through a thin
membrane. On the other hand, if starch is mixed with
saliva, and the mixture is key^t at the temperature of the
body, it is found in a short time that the starch has been
changed into sugar, which is not only soluble, but readily
diffuses through a tfun membrane. In other words, starch
as sucJi is useless to the rabbit as food; ‘only after it has
been digested by conversion into sugar can it be used by
the body.

Something very similar often takes place in plants. It
was seen (p. 33 ) that the cotyledons of a pea become
sweet during germination. Starch is a convenient form of
food for storing in the cotyledons of a pea, the endosperm
of the maize seed, the short stem of the crocus-corm, and so
on; but before the plant can use it as food the starch must be
made soluble and diffusible by being changed into sugar.
In plants the change is brought about, not by saliva, but by
a substance known as diastase.

The pancreatic juice continues the change of starch into
sugar which is commenced by the saliva, but it also digests
other food-stuffs as well. Similarly, gastric juice and bile
are each concerned with the digestion of certain foods.

THE RABBIT: CIRCULATION OF THE BLOOD 235

The result of the action — separate and combined — of the
digestive fluids* is that, when a rabbit eats no more food than
it requires, all the useful part of {he food is absorbed into
the blood, and then distributed teethe tis^es by the blood
as it flows through them.

46. THE CIRCULATION OF THE BLOOD.

T. Evidence of the circulation. — (a) The arterial Feel

your pulse at the wrist and count the number of beats per
minute.

{f}) The beats of the heart. — Similarly count how many
times your heart beats per minute. Put your car over the
heart of a friend, and listen to the sounds of the heart.
How many different sounds can you distinguish?

{c) The valves of the veins . — Press your thumb on your
arm inside the elbow, and then move it dowm the arm
towards the wnst. Notice the small knots which rise under
the skin between the point of picssure and the wrist.

2. The structure of a sheep’s heart.' — Procure from the butcher
a sheep’s heart wit^i, if possible, the lungs still attached. If the
thin transparent bag which naturally surrounds the heart has
been left on, carefully cut it away. Make out the main external
features of the heart before cutting into it. I'he shape is conical,
the apex of the cone being posterior, the base (where the blood-
vessels are attached) anterior. The ventral face is lounded ;
the dorsal face is flatter. Compare fig. 164. The line of fat
(j) marks the line of division between two chambers, the right
(A'. F.) and left (A. F.) ventricles. Feel that the right ventricle
yields to pressure more readily than the left. Two more
chambers, the right and left auricles., are situated at the basal
(thick) end. R.A. and L.A. are flaps of the right and left
auricles respectively. Identify the great vessels SVC and JVC
which discharge into the right auricle. Cut them open to sec

the entrance. Then lay open the right aurie’e. Pass your

•

^ More detailed instructions will be found in Foster and Shore’s Physio-
logy for Beginners (Macmillan).

236 AN INTRODUCTION TO NATURE-STUDY

finger down and notice that the right auricl^ communicates
freely with the right ventricle. Observe that y6u can from the
right ventricle pass your finger into the tube F.A. i make out
that this goes to t^^e lungs^i Lay open the left auricle, and see
that it receives vessels from the lungs. Pass your finger from
the left auricle into the left ventricle, and notice that this latter
chamber leads into the Aor/a, Ao. {A'o\ is a branch of Aof
Notice that the walls of the blood-vessels in connection with the
two auricles are collapsed, while those {}\A. and Ao) leading
from the two ventricles are more elastic and remain open.
Which of the two auricles has the thicker wall ? Which of the
two ventricles has the thicker wall ? Can you pass your finger
from one auricle to the other ? From one ventricle to the
other ? Cut away the auricles and pour water into the ven-
tricles. Then sf^ueeze the heart gently, and notice the flaps
which rise to close the openings into the ventricles. Could
blood pass from the ventricles to the auricles ? Why not ? Lay
open the bases of the vessels P.A. and Ao. leading from the
right and left ventricles respectively, and notice the pockets of
thin membrane whicli are attached there. Open them out
gently with the point of a pencil. Put the heart under the tap
and let water trickle down the vessels towards the ventricles ;
notice how the pockets stand out as they fill with water. What
would be the effect of blood trying to pass from P.A. or Ao.
back into their respective ventricles ?

The circulation of the blood. — The blood of such an
animal as the rabbit is contained in a system of closed tubes
called blood-vessels, through which the fluid is continually
flowing. The regular flow of the blood in one direction is
maintained by the action of the heart, a four-chambered
organ which is situated in the chest, between the lungs.
The heart is muscular, and, like other muscles (p. 225), has
the power of “ contracting ” in definite directions. The
contraction of the walls of the chambers of the heart lessens
their capacity, and therefore drives the blood out of them,
the direction of flow being determined by valves. The

THE RABBIT: CIRCULATION OF THE BLOOD 237

vessels which cjirry blood to the heart are called veins ; those
which transmit the blood which is pumped out of the heart
are called arteries. The arteries* branch into smaller and
smaller tubes which supply the various organs of the body,
and the small arterial branches divide again and again in
the organs until their finest ramifications form a close-
meshed network of vessels with excessively thin walls,
through which diffusion can readily take place between the
tissues and the blood. These finest blood-vessels are called
capillaries. They can be studied in the transparent web of
the frog’s foot with the aid of a low power of the microscope.
The blood can then be seen flowing, at a speed which varies
with the size of the vessel, its course being rendered obvious
by the tiny oval particles (red corpuscles) which are sus-
pended in it The smallest capillaries are so th in-wall ed
that they appear to be merely channels in the substance of
the web, and the corpuscles creep along in single file. But
these channels unite to form larger vessels with obvious walls,
and these unite ag^in and again until a main vein is formed
in which the blood, with its suspended corpuscles, rushes
along in a swift torrent towards the heart.

The heart. — The beginner will find the sheep’s heart
more convenient for examination than the rabbit’s, on
account of its larger size ; but apart from some difference
in the arrangement of the great blood-vessels opening into
them, the two hearts are broadly similar.

The heart (Fig. 164) consists of four chambers. Two of
these, the auricles, are receiving-chambers, and are placed at
the thick, anterior end of the heart. Into the right auricle
open the great veins {SVC, JVC,) which bring blood from
all parts of the body except the lungs ; the left auricle
receives only .blood from the lungs Each auricle opens
into a more posterior chamber called a ventricle, the right
auricle opening into the right ventricle and the left auricle

238

AN INTRODUCTION TO NATURE-STUDY

into the left ventricle. The ventricles pump,', blood into the
arteries. The blood from the right ventricle is sent into the
artery (P.A.) whi(^h supplies the capillaries of the lungs ; while
the blood of the left ventricle is forced into the aorta

Fig. 164. — Heait of Sheep, in position between
the luny:s. K.A., appendage of nuht auricle;
L.A.^ appendage of left auiicle; Vv.K., right
ventricle ; L. left ventricle ; S. y.C., 1 . V.L.,
great veins from the system generally; r,A.,
artery to lungs ; Ao,, aorta; A'o'., branch of
aorta ; lung ; J'r., wind-pipe, leading to

lungs ; 2, 3, 4, fat.

a great artery which
branches and supplies
with blood all parts of
the body except the
lungs. The two auricles
contract simultaneously,
forcing their contents
into the flaccid ven-
tricles. Then both the
filled ventricles contract
at once, and pump blood
into the great arteries,
flaps of membrane be-
tween the auricles and
ventricles preventing a
backward flow into the
auricles. Similarly the
bases of the great arteries
are provided with mem-
branous pockets which
readily admit the blood
from the ventricles when
these contract, but en-
tirely prevent a return

of blood to the ventricles. The appearance of these four

sets of valves, as seen from above, is .shown in Fig. 165.

After the contraction of the two ventricles there is a short

rest, then the auricles contract again and the A^hole process
is repeated.

The sounds which are heard when the ear is placed

THE RABBIT: CIRCULATION OF THE ^LOOD 239

over another person’s heart are often compared to the syl-
lables lub-dilp. The “lub” is partly caused by the contraction
of the ventricles ; the ,

^‘dup,” which immedi-
ately follows, is caused
by the sudden closure
of the valves at the
bases of the great ar-
teries. The throb of
the heart, which can
be felt from the outside,
is really the thrust of
the apex of the heart
against the chest wall at
each beat. The sudden
forcing of blood into
the already - full but
elastic arteries causes
a wave to travel ^long
these vessels, which can readily be felt, or even seen, at
places where a fairly large artery lies just beneath the skin.

Fkj. 165. — The orifices of the heat I seen frorp
above, the auiides and great vessels l»ciiig cut
aw’ay. PA^ wdves at Ijasc of arleiy to lungs;
Ao, valves at base of aorta; A\A.l\, onlice
between right auricle and ventiicle, with its
valves I7’ I, /.7'. 2, and y, L.A.F., orifice
between loft auricle and ventricle, with its valves
I and 2.

Fit.. 166. — l)iagrammatic sections
of veins with valves. In the upper
figure the blood is supposed to be
flowing in the direction of the arrow,
towards the heart ; in the lower,
back towards the capillaries.

Fig. 167. — A vein laitl open
to show a pair of pouch-shaped
valves.

1 #

This arterial wave is called the pulse. Many of the veins
are provided with pouch-shaped valves which permit the

240 AN ^INTRODUCTION TO NATURE-STUDY

blood to flow freely towards the heart, but, which bar the
passage of blood in the opposite direction.’ Their action
will readily be understood from Figs. i66 and 167.

The importan'^e of the capillaries. — The capillaries are
the least conspicuous part of the circulatory system, but
they are by far the most important. The heart, arteries, and
veins exist merely to renew constantly the blood which flows
through these minute channels. The excessive thinness of
the walls of the capillaries makes it possible for a ready
exchange to take place between the living tissue and the
blood, and the vessels themselves form a network of such
extremely close texture that it is practically impossible to
prick any living part of the body with a fine needle with-
out puncturing some of them and drawing blood.” The
work of the blood in supplying the various organs of the
body with food has already been referred to. We have
next to see how this all-important fluid is of service in
supplying the organs with oxygen.

47. RESPIRATION.

1. Carbon dioxide is formed when flesh burns. — Dry a piece of
meat and attach it to the end of a wire. Then light it, and
when it is burning vigorously lower it into a clean glass jan
When the flame goes out remove the charred flesh, and at once
pour a little clear lime water into the jar and shake up. The
lime water turns milky, showing the presence of carbon dioxide
gas in the jar. Examine what is left of the meat. It is charred,
showing that meat contains carbon. How was the carbon
dioxide formed during the burning ?

2 . Carbon dioxide is formed by the living body. — Breathe
through a glass tube into clear lime water, so that the air you
expel from your lungs bubbles through the liquid.. Does the,,lime
water remain clear, or turn milky ? Does the air you breathe
out contain a considerable quantity of carbon dioxide gas ?

THE RABBIT: RESPIRATION ^

241

Burning and life. — When a piece of the flesh of any
animal has befen dried it may easily be set on fire. The
burning is caused by the union of the constituents of the
flesh with some of the oxygen of the' air to fprm various gases.
One of these gases is carbon dioxide, formed by the com-
bination of the carbon of the flesh with oxygen. Carbon is
present in all the parts of animals and plants, as is evident
from the separation of charcoal (an impure form of carbon)
in the first stages of burning ; the carbon dioxide gas
which is formed may easily be recog-
nised by the milkiness which it
produces in clear lime water. The
liberation of heat, and the forma-
tion of carbon dioxide, which always
accompany the burning of animal
and plant tissues, are worthy of
very careful attention.

It is well known that the body of
a living animal suph as a rabbit or a
man is always war 7 n ; and the experi-
ment (Fig. 168) of passing through
clear lime water the air breathed out
from the lungs shows, by the milkiness ])rodueed, that the
animal is also constantly producing carbon dioxide during its
life. Is life, then, always accompanied by a peculiar form of
burning, in which the living substance of the body is the
combustible material? It seems so, and the experiments
of physiologists tend to confirm this view.

The necessity for breathing. — The energy which enables
a muscle to contract is derived from the oxidation — the slow
burning — of part of its substance, just as the energy which
enables a steam-engine to move is derived from the burning
of fuel in the* boiler fires. The fires soon go out, and the
engine stops, unless fresh fuel is added from time to time
N.S. Q

242

AN INTRODUCTION TO NATURE-STUDY

and a plentiful supply of air is available. Similarly, a muscle
loses its power of contracting, a gland that of secreting,
the brain that of thinking, ^unless the waste matters resulting
from previous activities fire cleared away and replaced by
fresh food and fresh oxygen. Wherever vital action is taking
place, whether in a contracting muscle, a secreting gland, or
a thinking brain, there is continual consumption of oxygen
and continual production of waste material, chiefly carbon
dioxide. In the higher animals tlie renewal of oxygen and
the removal of waste material are performed by the blood.
Blood-vessels are to the body what rivers and canals are to
a country : they act as highways for the transport of material.
We may perhaps carry the analogy a little farther and find
in the red corpuscles of the blood the rough equivalents of
boats or canal-barges, for they carry with them tiny loads of
oxygen. As the blood creeps along the narrow channels in
an active tissue the red corimscles relin(]uish their oxygen,
and the fluid portion of the blood takes up carbon dioxide.
The blood continues its course, and sooner, or later arrives at
a place where it can obtain a fresh supply of oxygen and get
rid of its surplus carbon dioxide. In the rabbit this exchange
takes place as the blood is- passing through the capillaries of
the lungs. There the blood is separated from the air by a
membrane so delicate that gases can readily pass through
it ; and, hence, on leaving the lungs the blood has got rid of
the waste carbon dioxide, and its red corpuscles are laden
with fresh oxygen. 77//s exchange of useless carbon dioxide
for oxygen constitutes respiratio?i or breath mg.

The mechanism of respiration.- In active animals the
air inside the lungs soon becomes vitiated, unless there is
some means of changing it. Under ordinary conditions a
man changes the air in his lungs from thirteen to
fifteen times a minute. He does this quite automatically,
and without thinking about it. Every four seconds or so a

THE RABBIT; RESPIRATION

243

set of muscles contracts and pulls his ribs upwards and out-
wards ; another muscular contraction pulls down the floor
of his chest at the same time. As ti consequence the cavity
is much enlarged. The lungs follow the iribvements of the
walls of the chest, and some thirty cubic inches of air are
sucked in. Immediately the ribs fall back to their former
position, the chest-floor rises, and aii is driven out. Then
after a short pause the process is repeated. It should be
noticed that only about thirty cubic inches of air are
changed at each respiration, although the capacity of the
human lungs averages about 230 cubic inches. All
mammals breathe in much the same way.

Plants and animals. — There are conj^’derably more
points of similarity than of difference between plants and
animals. In every case the vital activities are accompanied
by an oxidation of living substance, and from this fact arises
the necessity for food and oxygen. T'hc breathing of plants
is essentially like that of animals, and consists in taking in
oxygen and giving out carbon dioxide ; though the
mechanism of respiration is — except in the lowest plants
and animals — entirely different in the two cases. It is in
the sources from which they obtain their food that plants
and animals are most unlike. An animal must be supplied
with food which has already been prepared by some other
living thing ; and it is obvious that the food even (T
carnivorous animals can ultimately be traced back I0 plants,
for the flesh-eater preys upon the vegetarian. Animals are
therefore entirely dependent upon plants for food. In this
sense the saying ‘‘all flesh is grass'' is full of significance.

(Ireen plants (Chapter II.) are quite independent of all
other forms of life, and can build up their substance from
water, mineral matter, and the carbon dioxide of the air.
The taking in of carbon dioxide and giving out of oxygen
by gre^n plants has nothing whatever to do with respiration ;

244 AN INTRODUCTION TO NATURE-STUDY

it is part of their process of feeding. Green plants breathe
in the usual manner — by taking in oxygen and giving out
carbon dioxide. It should, however, be noticed that the
peculiar method' by which a green plant obtains its carbon-
aceous food is of the highest importance to animal life ; for
by this process the amount of injurious carbon dioxide in
the air is considerably lessened, while the proportion of life-
supporting oxygen in it is greatly increased.

Fungi (Chapter XL) seem to be intermediate, as regards
their method of feeding, between green plants and animals.
They require their carbonaceous food in an organic form,
that is, already prepared by other living things ; but they
can obtain th^^ other elements of their food from mineral
salts and water.

The thoughtful student will be increasingly impressed by
the extent to which the plant and animal kingdoms are
dependent upon each other, and Hy the manner in which
each utilises the waste products of the other for carrying on
its own life processes.

EXERCISES ON CHAPTER XIII.

1. Of what parts does the skull of a rabbit consist ? What is the use
of each part ?

2. Describe one of the long bones of a rabbit’s leg. To what features
does it owe its strength ?

3. The bones of the skeleton are useful (i) as affording points of
attachment for the muscles ; (2) as affording protection for delicate
tissues and organs. Give examples of each of these uses. Do not give
the technical names for the various muscles. (King’s Schol., 1902)

4. Draw and describe one of the middle joints of the backbone of a

quadruped, and explain the uses of the various parts. (1S98)

5. What is meant by “digestion”? Why must food be digested?
Where does digestion take place ?

6. Give full practical instructions for demonstrating the chief proper-
ties of saliva, and its action upon various kinds of food. (1897)

EXERCISES ON CHAPTER XIII.

245

7. Prove that the action of human saliva upon starch is not due to

living particles contained in it. (1898)

8. What are the chief uses of the bloods Why is it necessaiy that it

should be, kept in motion ? # (iQOi)

9. Where would you look for the Aorta in a sheep’s heart ? What

valves aje found in it ? How does it differ in ap[)ea)ance and feel from
a large vein? {1901

10. What kinds of valves are found in a sheep’s heart, and where are

they placed ? Describe a valve of each kind. (1898)

11. How does air breathed out from the lungs differ from common

air? How can the differences be demonstrated ? (1898)

12. Describe the process by which a mammal renews the air in its
lungs.

13. What is meant by ‘‘respiration”? Wtiy is respiration
necessary ?

14. Point out the most remarkable differences between the nutrition

of a green plant and that of an animal. (1897)

15. Name organisms which can derive nourishment from carbon

dioxide, from sugar, and from the dead bodies of animals. (1898)

16. What are the aimplest functions which distinguish living animal

matter from inanimate matter? (King’s Schol. 1903)

17. Explain as fully as you can how food taken into the stomach acts

U|X)n organs, such as the brain, which are not closely connected with
the stomach. I1904)

18. The uses of bone are, generally speaking, to protect delicate
structures, to support weight and to gain leverage. Illustrate this
statement by a simple description of one example of each type.

(Ceitificate, 1904)

19. The flow of liquids through the body is regulated in certain

localities by valves. Exjdain the action of a valve, and indicate where
they are to be found in the body. (Certificate, 1904)

20. In which kind of blood-vessel can the pul.se be felt? In which
kinds can it not be felt ? Explain the reason of the difference.

(Certificate, 1905)

21. How is oxygen conveyed from the lungs to the various parts of
the body? Describe what could be observed if a droj) of blood were
spread out on a piece of glass and examined under a microscope.

(King's Schf)l. 1905)

CHAPTI^R XIV.

SOME OTHER MAMMALS.

48. THE CAT AND DOD.

I. The external characters of the cat. — Carefully and gently
examine a cat, and make notes of the following characters :

(a) Hair. — What is the covering of the body like? Is the
hair like that of a rabbit, i.e. fur (p. 216)? Are the whiskers
very noticeable? On what parts of the head do they grow?
Are the fur and large whiskers in any way connected with the
animal’s habits ?

{li) Eyes . — Look at a cat’s eyes in a bright light. Is the pupil
(p. 212) round or slit-like? Keep the cat in the dark for a few
minutes and then look again at the ])upil of the eye ; has it
changed in form ? Is the change of any advantage to the cat?

ic) Teeth. — Cently open the cat’s mouth and examine the
teeth. Notice the sharp, pointed teeth behind the incisors
(p. 219); they arc called the canifie teeth. Has a rabbit any
canine teeth ? Why does a cat, and not a rabbit, need such
teeth ? Feel the remaining teeth with your finger ; are they flat
like those of a rabbit, or sharp-edged ? How are the characters
of the teeth associated with the kind of food ? Watch a cat
eating ; does it chew its food or swallow it “ in lumps”?

{if) Tongue. — Pass your finger-end over the cat’s tongue ; is
it rough or smooth ? In which direction of motion of the finger
does the tongue feel roughest ? Would the roughness be of any
help to the animal in licking meat from bones ?

(f) The limbs. — Measure the legs. Are the fore and hind

THE CAT AND DOG

247

limbs of equal length, slightly unequal, or very unequal? How
do they compare in this respect with the limbs of the rabbit?
Make out ‘the main bones by feeling through the skin, and
especially notice where the ankle-johit is. ^xamine the toes
and notice how, when you gently squeeze them just behind the
ends, the sharp claws protrude, and go back into a kind of
sheath when the pressure is removed. Can the animal put out
its claws and draw them back at will ?

2. The habits of the cat. — {a) F(wd — What kind of food does
the cat prefer, animal or vegetable? Docs it bolt its food
greedily, or does it cat deliberately and daintily ? Have you
ever known cats to hunt other animals? Do they hunt singly,
or do several cats join together to hunt ? How do tliey approach
the prey ; do they try to run it down by speed, or do they
creep up slyly and then spring? What is the^isc of the claws ?
How does a cat drink?

{b) Locomotion.— Watch a cat moving slowly ; does it walk or
hop ? Try to find out the order in which it puts its feet down.
How does it run ? Is it nimble or clumsy? Does the cat walk
with the whole sole of its foot on the ground, or does it walk
“on its toes”? •

(c) Likes and dislikes. — Do you consider a cat sociable, i.e.
fond, in general, of the society of other cats ? Do cats, as a rule,
show much appreciation of the difference between right and
wrong? Are they as affectionate as dogs? Have you ever
heard of any cat trying to remain in a house after the family had
removed to another house ? Are cats fonder of warm or of cool
places in a house ? Do they like getting wet ? Do they pay
much attention to personal cleanliness? How do they wash
themselves? Do you think the tongue is used as a comb?
How ? Can you know whether a cat is pleased or angry (i) by
the appearance and movements of the tail, (ii) by the sounds
which it makes ?

{d) Lntelligence. — Write accounts of cases of great intelligence
which you have known cats to show.

{e) Voice.— How do you describe a cat’s voice? How does
the voice vary according to the animal’s mood ?

(/) Play. — How does a cat play?

248 AN INTRODUCTION TO NATURE-STUDY

3. Kittens. — {a) Appearance .-— kittens helpless or active
when they are born? Is there any very marked difference
between the proportions of the body and limbs and those of a
full-grown cat ? ^t what Lge is a cat full-grown ?

{b) Play.—ViCTH does a kitten play ? How does it pretend to
“stalk” a small object, such as a ball of wool? In the same
way that a full-grown cat stalks a mouse ? Why does the kitten
adopt this method before it has any experience of liunting ?

{c) Education . — Watch a cat with its kittens, and describe
any actions which seem like education. Have you ever seen a
cat teach its kittens to fight ? Have you ever seen it punish a
kitten for disobeying a call ?

4. Tlie external characters of the dog. — Examine a dog in the
same way, and compare it point by point with the cat as regards
the following characters :

{a) Hair . — Notice that the dog is covered, not with fur, but
with rough hair, and that the whiskers are not very large. How
are these differences associated with differences in habit ?

{h) Eyes . — Notice that the pupil is always round, although it
is smaller in a strong light than in a weak one.

(^c) Teeth . — Compare the teeth with thor.e of the cat, and
notice that they are of similar form — with strong interlocking
canines and a sharp-edged tooth on each side of the upper jaw
which clips against a similar tooth in the lower jaw — but that the
cat’s teeth are more pointed.

{d) Tonyyie . — Notice that the dog’s longue is much smoother
than the cat’s.

(^) Limbs. — Examine and measure the limbs, comparing them
with those of the cat, rabbit, and man. Notice that the claws
are blunter than the cat’s, and that they cannot be withdrawn
into sheaths. How many toes are there on the feet?

5. The habits of the dog. — {a) Food . — Does the dog prefer
animal or vegetable food? Watch a dog gnawing a bone, and
observe the use of the clipping teeth. Does a dog eat greedily
or deliberately ? Does it chew its food or swallow it in lumps ?
Do dogs hunt singly or in packs ? Do they stalk the prey
stealthily, as cats do, or do they try to run it down by speed ?
Whenever possible watch a pack of hounds ; upon what sense—

THE CAT AND DOG

249

hearing, sight, or smell — do the hounds rely most ? How does a
dog drink ?

{d) Locohotion. — Does a slowly-moving dog hop or walk?
Try to find out the order in which it* puts it^ feet down. How
does it run ? Does a dog walk flat-footed or on its toes ?

{c) Likes and dislikes, — Do you consider dogs sociable or
Otherwise ? Do they seem to know the difference between right
and wrong? Are dogs affectionate ? Are they more attached to
the people or to the houses to which they are accustomed ?
What can you learn of a dog’s feelings, by the movements of its
tail ? Write accounts of instances, which you know to be true,
illustrating its likes and dislikes. What expression of the
human face seems to you most like the snarl of an angry
dog ? What are the resemblances ?

(d) Intelligence. — Write accounts of evidence of intelligence,
or reasoning power, which you have observed in dogs.

{e) Voice, — What is the ordinary voice of the dog ? What
other sounds do dogs make, and what do they mean ?

(/) Play. — How do dogs play ? Do you think dogs have any
sense of humour, or are able to appreciate a joke for the joke’s
sake ? Have you ever seen any expression resembling a smile
on a dog’s face ?

6 . Puppies.— (^7) Appearance. — Are puppies blind and helpless
when they are born, or are they active ? How soon can they
see ? Are the proportions of the body and limbs markedly
different from those of the full-grown dog ? At what age is a
dog full-grown ?

{b) Play, — Does a puppy play in the same manner as a
kitten ? What differences have you noticed ? Have these
differences any connection with the methods of catching the
prey of the adult animals ?

(c) Educaf ion.— Have you ever seen a puppy being taught to
do anything by its mother ? Write full accounts of such cases.

7. Different breeds of dogs. — Make notes of your observations
of as man]j different breeds of dogs as possible, e.g. collies,
terriers^ retridver, fox-hound, pointer, spaniel, etc., and de-
scribe the resemblances and differences in size, form, habits,
intelligence, etc.

250

AN INTRODUCTION TO NATURE-STUDY

The external characters of the cat and; dog. — The cat

and the dog are so commonly kept as pets that they are
perhaps more easily exarfiined than any other animals. In
addition, they ar^ so closely related and yet exhibit so many
differences that they afford a valuable exercise in the
methods of comparison and contrast which are at the founda-
tion of all successful work in Nature-Study. Several differ-
ences are at once apparent on even a casual inspection.
The body of the cat (Fig. 169) is covered with soft, smooth

Fig. 169.— The Cat.

///r, and its head is provided with long, sensitive whiskers.
In both of these respects it resembles the rabbit and other
mammals which are in the habit of creeping along narrow
and dark passages. It is commonly said that cats can see
in the dark. Although this is not altogether true— for no
animal can see in total daikness — the cat’s eyes have the
power of adapting themselves remarkably to the intensity of
the light. In a dim light, the curtain, or iris,* which sur-
rounds the pupil (the dark, central window through which
light enters the eye) is drawn back so as to admit as much

THE CAT AND DOG

251

light as possible ; whereas in a very bright light the curtain
is so nearly closed that the pupil is merely a narrow, vertical
slit. On \he other hand, the do^ (Fig. 170), which is not
fond of dark passages, has its body cl/thed with rough
hair^ instead of fur; and its whiskers are not nearly so
long as those of the cat. Again, although the iris of a
dog’s eye alters in size to regulate the amount of light

Fig. 170. — Foxhound.

entering the eye, the pupil is always round, and the change
of size is much less marked than in the cat. Another very
noticeable difference is in the claws at the ends of the toes,
corresponding to the nails at the ends of our own fingers
and toes. In the cat these are sickle-shaped and extremely
sharp, and are kept drawn completely back into sheaths
when they are not required. The dog’s claws /are blunt*
and cannot be retracted. Both the dog and the cat rest
the weight of the body upon the toes— not upon the sole
of the foot — when walking or running.

252 AN INTRODUCTION TO NATURE-STUDY

There is also a very marked difference iri the tongues of
the two animals. The tongue of the cat is rough, with small
points directed backwards. These points are of great help
in licking the fle^sh from bones ; and they also serve as a
comb when the cat — which is fastidious about the cleanli-
ness of its fur — “ washes ” itself. The tongue of the dog is
smooth and moist

The inherited habits of the cat and dog. — Very obvious
differences are also to be seen in the habits of the two
animals, and these would be somewhat difficult to explain if
we confined our attention to the domesticated animals only,
which live under artificial conditions. When, however, we
consider the wiy relatives of the cat and dog, many of the
differences become full of significance. The wild animals
of the cat family, almost without exception, are either
solitary or live in pairs ; whereas the wild dogs (wolves,
jacl<aTs7^c.7*Trui m‘p^ The habits which these respective
methods of lile'Tntailecl have become so firmly implanted
in the nature of the race that even now, filter thousands of
generations of domestication, they may be traced. Such
inherited habits, which are not dependent upon, or may be
at variance with, present conditions of life, are called
Instincts.

We will first see how the ancestral custom of living in
organised packs has left its impress upon the instincts of the
domesticated dog. The first essential to the success of any
community of animals— whether these are bees or rooks,
wolves or men — is that all the creatures composing it shall
conform to certain rules, which have for their object the
good of the community and not merely that of the in-
dividual. Acts which promote the wellbeing of the society
as a whole are good, and are directly or indirectly rewarded.
Acts which tend to injure the society as such are bad, and
inevitably bring punishment either to the individual offender

THE CAT AND DOG

253

or, what is worse, to his pack. A distinction between right
and wrong is thus established which would be impossible to
any animal living so solitary a life»that its acts affected only
.itself. In this manner were aroused the j^ocial instinct, the
love of praise and the dread of shame, the lifelong attach^
ment to early friends, and almost all the other qualities
which have so endeared the dog to mankind; because these
qualities resulted naturally from the ancestral pack-life.
Left to it^ejfj the dog loses its nerve, for it is by nature
unfitted for a solitary life, WKat more woe -begone dnimal is
ever seen tharV a lost dog ?

Contrast the cat in these respects. It is at heart an out-
law, like its wild ancestors: recognising, in general, no motives
but those of its own ease and gratification. Its social instinct
is almost absent; and though it sometimes displays affection
to people who pet it, the cat is, as a rule, more attached, to
places than to persons. It retains, too, the independence
and "versatility whTcli are developed by a solitary life. A
lost cat can usually take care of itself and find sufficient
food ; and cases are not uncommon of cats leaving com-
fortable homes and choosing to live wild lives in the woods.

Ancestral methods of hunting also account largely for
certain differences in the domestic cat and dog. The soli-
tary ancestral cats, like the lions and tigers of to-day, sprang
suddenly upon the prey at the end of silent, stealthy stalking.
How firmly this method has become fixed in the character
of the race may be seen still in the manner in which a cat
stalks a mouse or a small bird, or even, in play, a dead leaf.
At the final spring the sharp, sickle-shaped claws are used
to hold down the victim. The solitary hunter is able to
devour its capture at leisure, and the domestic cat is still
distinguished .by its dainty and deliberate manner of feeding.

The wild dogs hunt in a quite different manner. The
whole pack joins in the chase, the trail being followed by the

254 AN INTRODUCTION TO NATURE-STUDY

sense of smell. There is no attempt at concealment, no
stealthy stalking ; but an open reliance upon speed, endur-
ance, and numbers, rather than upon cunning. If one dog
loses the scent Jtnother picks it up and gives the signal.
Mutual help is thus the secret of success in hunting. But
this is at an end when the prey is killed. The victim is
torn to pieces and devoured greedily, each animal eating as
rapidly as possible, for in most cases there is not enough to
satisfy them all. And ^ domestic dog still betrays

the ancestral necessity for hurried eating in the manner of
bolting his food.

Metlidds of expressing feeling. — Animals express their
feelings in varipus ways — by the voice, by the face, by the
tail, and by the general attitude of the body. Perhaps no
animal’s feelings are more readily recognised by man than
the dog’s. “It is a remarkable fact,” says Darwin,^ “that
the dog, since being domesticated, has learnt to bark in at
least four or five distinct tones. Although barking is a new
art, no doubt the wild parent-species of S:he dog expressed
their feelings by cries of various kinds. With the domesti-
cated dog we have the bark of eagerness, as in the chase ;
that of anger, as well as growling ; the yelp or howl of
despair, as when shut up ; the baying at night ; the bark of
joy, as when starting on a walk with his master; and the
very distinct one of demand or supplication, as when wish-
ing for a door or window to be opened.” The movements
of the tail are also full of meaning, and capable of expressing
several different moods. It seems likely that in a dog the
movements of the tail were originally of use chiefly to
signal to the rest of the pack. The use of the movements
of a cat’s tail is not very clear, although these also differ
according to the animal’s feelings.

Carnivores. — Dogs and cats, with several other mammals,
^ The Descent of Man, Cheap edition, is. (Murray),

THE BAT

255

which are mostly flesh- eaters, are called Carnivores. They
have never fewer than four distinct toes on each foot, and
the claws (nkails) are often cap-
able of being withdrawn into
sheaths. The teeth (Fig. 17 1)
are characterised by the large,
interlocking canines, which are
conical, curved, and pointed;
and by one of the cheek-teeth
on each side having a sharp,
cutting edge which bites against
the similar tooth of the ntBpr almost in the of

the blades of sciss ors. The seals and walruses, however,
which are carnivores adapted to living in water, have no
such clipping teeth.

49. THE BAT.

1. Habits, — At what time of the year have you seen bats flying
about? Do they fly in broad daylight, or only in the evening?
How can you distirl^iiish a bat’s flight from that of a bird?
Have you ever heard a bat squeak ? Upon what does it feed ?
Are flying insects plentiful in winter? Have you ever seen
a bat drink ? How does it drink ? What does the bat do in
winter? Try to find a sleeping bat in winter in a barn, a hollow
tree, or a belfry ? What is its position ?

2. Appearance.— Examine a sleeping bat or a stufled specimen.
What is its body covered with, hair or feathers ? Is it a bird or
a mammal? Is the hair soft and furry? How large are the
ears? Are the whiskers large or small? What are the wings
like? Can you see any fingers? How many fingers are there ?
Do any of the fingers bear claws ? Do the fingers support the
wings? Which are longer, the fore limbs or the hind limbs?
Do the toes of the hind limbs bear claws? What is their use?
If possible, put a live bat on the ground ; does it walk easily?
Apart from the'wings, what animal does the bat seem most to
resemble ? Do you know of any other flying mammal ?

256 AN INTRODUCTION TO NATURE-STUDY

The Bat (Figs. 172 and 184^?). — On summer evenings in
most country districts of Britain bats may be seen flitting
about catching insects. The flight is peculiar, and somewhat
suggestive of that pf a butterfly, so that even in the dusk
the animal may be distinguished easily from a small bird,
“ Bats drink on the wing like swallows, by sipping the
surface as they play over pools and streams. They love to

Fio. 17?. — The Bat. (x^.)

frequent waters, not only for the sake of drinking, but on
account of insects, which are found over them in the greatest
plenty.’'^

The voice of the bat is a shrill squeak; of so high a pitch
that many people cannot hear it at all. The animal is
probably quite blind, but it has keen powers of scent and
hearing, and in avoiding obstacles seems to be greatly aided
by patches of specially sensitive skin on the face, and by
delicate whiskers. During the day it lurks in dark corners
of barns, church-tower.s, hollow trees, etc., hanging head
downward by the hooked claws of its hind feet.

On close examination the body of the bat is seen to be
covered with soft fur, a character which at once proclaims
the animal to be not a bird — as it has been incorrectly
considered — but a mammal. The fur is often of a bright
chestnut colour. The ears are large and practically devoid
of hair, and are so thin as to be almost transparent. The

^ Gilbert White, The NcUural History of Selbome.

HOOFED MAMMALS 257

wings are thin folds of skin, which are attached in front
to the long arms, are supported by the greatly elongated
fingers, and reach to the hind liqjbs. Another membrane
passes between the hind limbs, and in common species is
also supported by the tail The thumb fs free, and bears
a claw which is of some assistance in climbing. The hind
limbs are small.

The structure of the bat is obviously but little adapted to
walking, and the animal moves about very awkwardly when
on the ground, although it can rise on the wing again
without much difficulty.

The bat is rarely to be seen abroad after the middle of
November, for as the cold weather approaches and insects
become scarce, it suspends itself by its hind^ claws in some
dark and sheltered corner, and goes to sleep for the winter,
reappearing in early spring.

50. HOOFED MAMIVIALS.

I. The external characters of the sheep. — {a) Wool . — How does
the covering of a sleep’s body differ from the fur of a cat or
rabbit, and from the hair of the dog ? Examine a lock of “raw”
wool ; is it at all greasy ? Dip it in water ; is it much wetted ?
Are^the fibres easily entangled together? Why is woollen
clothing so warm ?

{b) Teeth . — Obtain a sheep’s head from the butcher, and
examine the teeth. Notice the absence of incisors and canines
in the upper jaw, and of canines in the lower jaw. Observe the
thickened pad on the surface of the upper jaw’, against which the
lower incisors bite. Are the cheek teeth flat, or sharp-edged like
the cheek teeth of carnivores? Watch a sheep feeding, and
notice how it bites the grass. How is the lower jaw moved
during the chewing of the cud ?

(r) Horns . — Which sheep have the largest horns, the males
(rams) or the females (ewes)? If you can find a cast horn
notice whether it is hollow or solid. What is the use of horns ?

{d) Limbs . — Is there any marked difference in the lengths of
N.S. R

258 AN INTRODUCTION TO NATURE-STUDY

fore and hind limbs ? Notice the hoofs which cover those parts
of the feet touching the ground. How many hcofs are there on
each foot ?

2. The habits of the sheepr— Are sheep solitary or cfo they live
in flocks ? What Jdnd of ground do they seem to prefer, flat or
hilly ? Are sheep ’on a hillside easily seen from a distance ?
Why not ? Are sheep nimble or clumsy? Can they run very
fast ? Would a flock of sheep be safer from, say, wolves on a
rocky hillside or on an open plain ? In a grazing flock of sheep
notice whether most of the animals have their heads turned in
the same direction. Has the direction any relation to the
direction of the wind ? Can you explain this ?

In a running flock of sheep does any one animal act as leader?

Is the leader a ram or a ewe ? Is it a lamb or an old animal ?

Do the rest of the flock imitate the actions of the leader, and,

♦

for example, leap over a wall at the same ]’)lace in single file ?
Have you ever noticed that if one animal jumps at a certain
place, all the following sheep jump at the same place? Have
you ever seen sheep fighting ? Were the combatants rams or
ewes ? How did they fight ?

What is the voice of a sheep like ?

3. Lambs. — Appearance ~ hx what time of the year are
lambs born? Are they helpless or active? Have they long
legs ? What advantage to the lamb is length of limb ?

{H) Play . — Watch lambs playing. Do they show a pre-
ference for any eminence, e.g. a rock, in the neighbourhood ?
What is the meaning of this preference ? How do lambs fight ?
Have you ever seen a ewe stamp with her fore feet when anyone
approached her lamb ? ^ At what age is a sheep full grown ?

The sheep. — The sheep (Fig. 173) differs in several
important respects from any of the animals previously
mentioned. It is of course a mammal, for it suckles its
young, and its body is covered by hair ; but the hair is of
that warm fleecy kind which is called wool. The fibres of
wool are seen under the microscope to be rough and scaly.
For this reason they can be spun into loosely-textured threads

HOOFED MAMMALS

259

which entangle, a great deal of air; woollen garments are
thus very bad conductors of heat. The wool upon the
sheep’s bc^dy is slightly greasy, fuDm a substance which is
given off by the skin and protecfs the ^inimal from rain.
The toes of the sheep are not armed with ordinary nails or
claws, but claws are represented by horny masses called
hoofs, which (mease the ends of the toes, and upon which

Fig. 173. —Sheep.

the whole weight of the body is thrown. The sheep, especi-
ally the male (ram), is often provided with weapons in the
form of hollow horns, which grow upon its forehead.

Method of feeding. - The sheep is a strict vegetarian,
living largely upon grass. It grips the grass between its
lower incisor teeth and a hard pad on the upper jaw ; there
are no incisor teeth in the upper jaw. Neither upper nor
lower jaw bears canine teeth ; and the cheek teeth, which
are used for chewing the food, have their crowns ridged
lengthwise. /Fhe arrangement of the teeth of the sheep is
shown in Fig. 174. During grazing, however, the food is not
at once chewed, but is simply mixed with a large quantity of

260

AN INTRODUCTION TO NATURE-STUDY

saliva and swallowed, the chewing-process being performed at
a later period. It is obviously a great advantage to an animal,

which in the wild state is
liable at any moment to
be attacked by enemies,
to be able to stow away
its food quickly, and
afterwards masticate it
at leisure. This is ren-
dered possible, in < ^en ,
sheep, goats, d^er, and
the few other animals
which chew the cud,
by the peculiar form
of stomach shown in
Fig. 175. The hastily
swallowed food is passed
into the large paunch {/?)
and into the compart-
ment c. When the animal finds an opportunity of
“ruminating” or chewing the cud, the food is returned
to the mouth in small
quantities at a time,
and is there finely
divided by the cheek-
teeth. In this condi-
tion it is again swal-
lowed, and makes its
way at once into
the compartment d,

where it is strained Fig. 175.— stomach of a Ruminant opened to show
, , the internal structure. For description, see text.

between leaf-like

folds and then passed into the last chamber (<?), and thence
to the intestines, to undergo the final processes of digestion.

HOOFED MAMMALS

Ruminants.-*- Animals which, like the sheep, oxen, goats,
deer, etc.,, ruminate or chew the^cud in this manner, are
called ruminants. In all '-ruminants the
weight of the body is supported by t^e jAl
tips of the third and fourth toes of the
feet, the remaining toes either having com-
pletely disappeared or remaining very small 9

(Fig. 176). The tips of the toes are en-
cased in horny hoofs, which represent greatly
enlarged claws or nails. The ruminants
therefore belong to what may be called

the even-toed hoofed mammals. v

/ hoofed mammals, but they

are not ruminants, because,
having simple stomachs, they
do not chew the cud.* ^ ^

||\ Other hoofed mammals. ^ jw
li ^ horse and donkey

I I the reduction of the number Fig. i76.-Bones

I I of toes has gone still further ;

I ■ for these animals have now i lower.)

only the third Or middle toe of each foot left
(Fig. 177) ; and because it has to carry the
ill whole weight of the body, it has become
. pm very large and stout ; its tip is encased in
a hoof.

The hoofed mammals are therefore divided
-nr into two groups :

of^7o«?V7o?°"of i^) odd-toed, including the horse and

^(Aftir Flower.) simple stomachs, and there-

fore do not chew the cud) ; and
(2) the even-toed, including (^) ruminants like the sheep, etc.,
and (b) such non-ruminants as the pigs and their relatives.

Fig. 177. — Bones
of fore - foot of
Horse.

^ (After Flower.) ^

262

AN INTRODUCTION TO NATURE-STUDY

The inherited habits of the sheep. — As /n the cases of
the dog and cat, so in the sheep, the true explanation of
several curious habits iSt to be found in the manner of life
of the wild anc(5stors ; for it must be remembered that
domestication, however kindly an animal may take to it, is
an artificial condition of life. Wild sheep live in flocks, as
a rule in cold and mountainous

sath3Tt’irnnier(S^“a^^^ if they are not to be at the mercy of
savage carnivores. An old and experienced ram is generally
in charge of the flock, and in case of alarm he leads the
way to a more inaccessible position. The rest of the flock
follow in single file, closely imitating his every movement,
leaping without* hesitation — and therefore saving valuable
time — wherever he has leapt. The survival of this instinct
in domestic sheep may be observed whenever a flock is
travelling along the road. Even young lambs still display a
decided preference fc^^r rocks, hillocks, and other elevated
positions. Wild sheep, being so liable to sudden interrup-
tion when grazing, are enabled by their compound stomachs
to swallow food quickly and postpone the chewing process
to a more favourabl® opportunity. Sentinels usually keep
watch, and warn the flock of approaching enemies by stamp-
ing their hoofs on the ground, an action which may still be
seen whenever a ewe fears danger to her lambs.

The play and education of the young — The young of
mammals are usually under the care of the mother for
education and protection until they are nearly adult ; and it
is generally found that the longest infancy (in proportion to
the natural life of the animal) occurs in the most intelligent
races. The importance of the play and education period is
very great, for it not only gives the young animal an oppor-
tunity of training its natural faculties in comparative safety,'
by exercise of various kinds and by games with companions
of its own age and strength ; but it allows the mother to

EXERCISES ON CHAPTER XIV 263

impart, by direct instruction, some of the experience which
she has personally gained during her life. The extent of
this maternal education is greater* than has been generally
supposed ; and every opportunity shoiAld be taken of
observing and recording cases of it.^

The play of young animals also in many cases gives
important clues to lost ancestral habits, which are not
now to be seen in adult life. The inherited tendency of
animals to repeat, during their own development, the
history of their race is very great ; some striking cases of
this will be considered in later chapters.

EXERCISES ON CHAPTER XTV.

1. Make a list of cases which you have observed of protective

colouration in mammals, specifying («) the colour of the animal, {b) the
colour of its surroundings. •

2. Describe any cases w’hich you have observed of mammals having
differently-coloured coats in summer and winter. Of what use is the
change in colour ?

3. Make a list of the mammals you know from observation to walk
[a) flat-footed, {b) on their toes, (c) on the tips of their toes.

4. Make a list of the mammals which habitually hop, walk, fly, nnd
swim respectively ; nnd And out, by oliscrvation if possible, how the
structure is adapted to the method of life.

5. Study the habits of the mole, and try to discover by what
modifications it is enabled to burrow so rapidly.

6. What is the difference in the ways in which cows and horses get
up and lie down ?

7. For what purposes do the following mammals use their tails —
cows, squirrels, rabbits? Wliat mammals do you know' which are
without tails?

^ See Lloyd Morgan’s Habit and Instinct {Kxno\ 6 ), Thompson-Seton’s
Wild Anitnals I have knenvn (Nutt), and Long’s School of the Woods
(Ginn).

264 an introduction TO NATURE-STUDY

8. Observe and describe the differences — apart from speed — between
walking, trotting, and galloping, in the case of the horse.

9. Describe how you have ‘tamed any wild animal. Why is it easier
to tame a young animal than* an old one?

10. Describe case^ of mammals showing antipathy to certain colours,
flow do you explain the dislike ?

ir. Which domestic mammals are (a) most shy, (<5) most inquisitive,
(c) most gentle, {d) most suspicious, (r) most intelligent ?

12. Of what shape is the pupil of the eye in a dog, a cat, and a

sheep ? Does the shape of the pupil change from time to time in any
of these animals? (1898)

13. Describe the fore-foot of a cat, a dog, and a sheep. The bones

of the foot need not be described in detail. Draw a footprint of
each animal (fore-foot), and show how each part of the print is pro-
duced. ' (1898)

14. Give a short account of the life of a bat. When and where does

it seek its food ? How does it pass the winter? (1898)

15. Give illustrations (from your own experience if possible) of the

curiosity of dogs and cals. Show that their curiosity is necessary to
their welfare. (1901)

16. Mention animals which are nocturnal (only coming forth at

night), animals which burrow in the ground, animals which are solitary,
and animals which are social. (1901)

17. How are young cats treated by their mother when they are

helpless, when they first run about freely, and when they are able to
get their own food? (1903)

18. Mention some of the peculiarities which serve in most cases to
distinguish the hind limb of a quadruped from the fore limb. (1905)

19. The habits of an animal can be inferred from its teeth.* To what
extent is this statement true of {a) the cat, (d) the rabbit ?

(King’s Scholarship, 1905)

CHAPTER XV.

the PIGEON: A TYPICAL BIRD.

5lf HABITS AND STEUOTURE OF THE PIGEON.

1. General observations upon tlie‘%ovecote pigeon. — Watch a
group of pigeons. What is the shape of the body ? With
what is the body covered ? What is the colour of the feathers ?
Does the bird walk or hop ? How many walking limbs has it ?
Has it any other means of moving fjom place to place, in
addition to walking ? How many wings has it ? Are the wings
anterior or posteri( 5 r (p. 217) to the legs? Watch a pigeon
preening its feathers ; why does it apply its bill so frequently to
its tail ? Can the bird bend its neck easily in all directions ? On
what do pigeons feed? How do they pick up their food? Do
they chew the food ? What is the voice of the pigeon like ? At
what time of the year do pigeons moult ? How many eggs does
the hen-pigeon lay ? What is the colour of the eggs ? What
are newly-hatched pigeons like? How do the parent birds
feed them ?

Try to find a wood-pigeon’s nest. What is its shape ? What
js it made of? Is the top open or closed-in ?

2. The eirtemal characters. — Closely examine a dead pigeon in
respect of the following features :

{a) Feathers . — In what direction do the free ends of the
feathers point ? Where are the longest feathers ?

{b) The hedd . — What is the general shape of the head?
Notice the horny bill ; is it blunt, pointed, or hooked ? Does it
bear teeth ? Observe the cere.^ a whitish patch of swollen skin at

266

AN INTRODUCTION TO NATURE-STUDY

each side of the base of the upper beak, and surrounding the
7iostnl. Examine the large eycs^ and notice the upper and
lower eyelids and the tnlhsparent third eyelid. I^ind the ear-
openings a little below and behind the level of the eye, and
hidden by the small feathers of the neck. Open the mouth and
see the pointed temgUe,

{c) The neck . — In the feathered bird this appears short ; it
will be better seen after the removal of tlie feathers (contour
feathers) which cover it.

{d) The Zr//;//’.— What is the apparent shape of the trunk?
Where is its heaviest part ?

ie) The wings. - Open out the wings fully and measure the
distance from tip to tip ; compare it with the length of the
trunk. Which surface, upper or lower, of the expanded wing is
rounded (convex) and which is hollowed (concave)? Put up an
umbrella and, holding it by the handle, move it quickly (i) away
from you, (ii) towards you. In which direction of motion does
the air offer more resistance? Is it an advantage for the
expanded wing to be c;pnvex above and concave below ? Why ?
Feel the wing-bones through the skin, and notice that the wing-
skeleton consists of three parts corresponeJing to the bones of
your upper- arm, fore-arm, and hand (with the wrist) respectively ;
and that they are bent on each other in the form of a Z when
the wings are folded. 'The large quill -feather's attached to the
segment which corresponds to the hand and wrist are called
priitiaries ; count them. Those attached to the fore-arm are
called secondaries ; count them. Find the tuft of smtiller feathers
which spring, at the front edge of the wing, from the thumb ;
this tuft is called the Ihunib-wing, The primaries and
secondaries collectively may be called the rowing feathers.
Notice the smaller feathers which, on both the upper and lower
surface of the wing, cover the quills of the primaries and
secondaries ; these smaller feathers are called the wmg-
coverts.

(/) The Iegs.—Y(tQ[ the leg-bones through the skin, and
make out the various segments. Is the whole of the hind-limb
feathered ? Which part is devoid of feathers ? With what is
this part covered ? How many toes are there ? Do any point

THE PIGEON

267

backwards ? Stratch out the legs and notice that the toes open.
Bend the ankle-joint and notice that the toes close auto-
matically. Of what use is this in peroiiing?

The tail . — Examine the tail and notice the large quill-
feathers attached to it ; count them. As ihc^^ are largely used
for steering during flight they are sometimes called the steeling
feathers.

3, The feathers. — Examine the arrang^ement of the feathers.
The short feathers which clothe the body generally are called
co 7 itour feathers because they determine the contoui of the
unplucked bird ; remove one or two and place them aside. The
feathers which cover the bases of the large quills arc called
cove 7 'ts — wing-coverts or tail-coverts according to their position.
Remove one or two for future examination. Examine the
arrangement of the quill-feathers of the wings, ‘^and notice how
the vane or web of one partially overlaps the next. 'T'hc vane is
supported by a shaft. Are the two sides of the vane of equal
width? Is the narrower side directed forwards or backwards ?
Pull out a quill-fcather from each win^' and compare them.
How could you recognise, if you did not know, whether any
particular feather Imd come from the right or from the left
wing? Pull out a (|uill-feather from the tail ; are the sides of
the vane of equal width ?

4. Examination of various feathers. —Examine in detail a quill-
feather from the wing. Make out :

(/z) The quill. - Is it hollow or solid? Try to bend it and
notice its great strength. Observe the small hole at its base.

{T) The shaft. - is the prolongation of the quill, and
carries the web or vane. Is the shaft hollow or solid? Notice
the small tuft of down on the inner face of the feather, at the
junction of the quill and shaft.

{c) The Hold up the feather to the light and examine

the vane with a lens. Notice that the vane consists of a number
of laths which spring from- the shaft; these are callicd ha?'bs.
Try to separate the barbs, and observe that they offer consider-
able resistance to the pull, as if they were somehow fastened
together. Examine a barb with a strong lens and observe the
finer branches, called barhules.^ which it bears. The barbules on

26S

AN INTRODUCTION TO NATURE-STUDY

one side of the barb carry little hooks, while {those of the other
side beait flanges, on which fit the hooks of barbules carried
by the next barb below. The hooks and flanges cajmot be seen
with out a mic roscope. '

{d) Other feathers. — Compare the covert and contour feathers
with tht quill feathers. Observe, in the contour feathers, the
less perfect interlocking of the barbs of those parts which are
covered by other feathers.

Pluck the pigeon, and notice the hair-like structures left in the
skin. They are called filoplumes. Pull one out and examine it
with a lens ; it bears a few barbs at its upper end, but these do
not interlock.

Examine a nestling'pigeon, and notice the downfeathers
which clothe it temporarily. Each is at first covered at the base
with a horny shfeath. The barbs do not interlock. The down-
feathers are pushed off by the growth of the permanent feathers.

5. The plucked pigeon.— -Observe that feathers do not grow on
all parts of the body, but are confined to definite feather-tracts^
which can be recognised by the scars left by the quills. Notice
especially the sockets of the large wing- and tail-quills. Make
out the oil-gland., a small knob just above the tip of the true tail.
It furnishes a lubricating fluid used in preening the feathers.
Examine more closely the different regions of the body — the
neck, the joints of the limbs, etc., which were disguised by the
feathers. The filoplumes have already been seen. Feel the
great muscles of the breast., and the edge of the sternum or
breast-bone in the middle line. Just in front of this feel the soft
crop, with the grain which is probably present in it.

Before boiling the bird in order to separate and examine the
bones, open the crop and inspect its contents. Cut away the
enormous muscles of the breast (why are they so large ?) and
open the body-cavity behind and remove the internal organs,
being careful not to break any bones.

6. The skeleton. — Boil the bird until the flesh can be easily
removed. A small nail-brush will be found useful in cleaning
the bones. Keep as many of these in contact as possible, and
make out and examine the following parts ;

(a) The skull, with the rounded brain-case, horny beak, and

THE PIGEON

269

large eye-sockets.^ Notice, at the back of the skull, the single
knob, which fits ihto a hollow on the first vertebra.

{b) The backbone, — Notice the long neck, the fusion of many
of the vertebrae in the trunk-region^ and, at the end of the
tail, the “ploughshare bone.” This last suppj)rts the tail-quills.

{c) The breast-bone,, or sternum, produced ventrally into a thin
plate called the keel (to which were attached the great muscles
of the breast), and connected by ribs to the backbone.

{d) The position of the shoulder joint,, and the socket for the
bone of the upper-arm. Notice the V-shaped “ merrythought.”

{e) The bones of the fore-limb (wing).— Make out the parts
belonging to the upper-arm, fore-arm, and wrist and hand, and
notice that the bones of the wrist and hand are firmly fused
together to give increased strength.

(/) The large hip-bones. — Notice their forward extension and
fusion with the joined vertebrae of this region, and the resulting
increased firmness of this part.

(^) The bones of the hind-limbs.

7. Pneumatic bones. — Examine the bone of the upper-arm of
the pigeon and notice, just below the head of the bone, a small
hole which leads intg the interior. Break the bone across ; is it
hollow or solid ? Does the inside contain marrow ? How does
it differ from the corresponding bone of a rabbit ?

8. Different breed8.~Examine various breeds of domestic
pigeons, and compare them with the common variety, as regards
colour, shape, method o^ flight, extent of feathering of the hind-
limbs, etc.

Birds. — It is probable that no class of animals has been
more studied than that of the birds; and the reasons for
this are not difificult to find. The wonderful power of
flight — rivalled only by the insects — and the perfect adapta-
tion of structure to this power ; the habits, always interesting
and in many cases showing a curious parallelism to human
institutions ; tlje beautiful voices of song birds ; the grace of
movement ; the mysteries of migration ; and, it may be
Added, the rqjrpAlkable story of the origin of birds which has

270

AN INTRODUCTION TO NATURE-STUDY

been revealed by modern zoology, — form a combination of
characteii, at once familiar and elusive, which has greatly
Stimulated human sympathy and imagination. It is well to
begin the study of bird's by first taking one familiar species
and examining it somewhat closely, and afterwards compar-
ing and contrasting other members of the class. Such a
convenient type for study is found in the dovecote pigeon.

The pigeon. — The body of the common dovecote pigeon
(Fig. 178) is ovoid in shape, tapering gently at the neck and

Fig. 178. - Pigeons.

appearing, in the living animal, to pass insensibly into the
head. The fore-limbs are modified to form a pair of wings,
which are set on a little above and in front of the centre of
gravity of the body. Except during flight the weight of the
body is entirely supported by the hind-limbs or legs, which
are fixed almost exactly below the centre of gravity of
the body, i.e. in the best imaginable position. Each foot
bears four toes, the first of which is directed backwards.
Each toe is armed with a claw.

The body generally is clothed with feathers, remarkable
structures which are as characteristic of birds as hairs are
(p. 220) of mammals. The great majority of the feathers
are small, overlapping and plate-like, with their free ends
pointing backwards ; and they form a light, warm, and

THE PIGEON

271

smooth covering which is admirably adapted to the animal’s
needs. Certain » large feathers, carried by the’ wings and
tail, are used in flight. The legs are feathered to tlie ankle-
joint, but the feet are covered oijly with scales. The
general colour of the dovecote pigeon is a sjaty blue.

The head is rounded, and terminates in front in a horny
bill, which does not bear teeth. At the base of the upper
beak there is, on each side, a whitish patch of swollen skin
called the cere, which surrounds the opening of the nostril.
The eyes are large and round ; in addition to upper and
lower eyelids, each is provided with a transparent third
eyelid, which can be flicked rapidly across the eyeball.
Birds generally have very powerful sight and depend more
upon this sense than upon any other. There are no
external ears, but when the feathers are separated, a little
below and behind the eyes, a pair of apertures leading to
the internal ears may be seen.

Habits. — The pigeon lives upon graip, which it picks up
by means of its horny bill. The length and flexibility of
the neck are a great'* help in feeding. 1'he food is swallowed
immediately and passed into a large bag called the crop,
which is really a dilatation of the lower part of the gullet.
Here it is macerated for some time before it passes onward
to the true stomach. The hinder part of the stomach is
called the gizzard ; it has very thick walls and a hard horny
lining. In the gizzard the food is ground up by the aid
of small stones which the pigeon swallows for the purpose.
The stomach is followed by a much-coiled intestine, in'
which the process of digestion is completed.

The pigeon differs from 'many birds in walking instead of
hopping. When perching, it bends its legs at the ankles, an
action which automatically closes the toes in such a manner
that the perch is grasped behind by the first toe and in front
by the second, third, and fourth. The weight of the body is

272 AN INTRODUCTION TO NATURE-STUDY

sufficient to maintain a tight clasp upon the perch, so that
the bird is al)le to sleep comfortably in this position.

hind-head {occiput)

ear coverts , auricular^

nape (nucfta)

hind-nedi {cervioc)

back {dorswrCi^

acapulars-";^^

crown {vertex) . ,

\orb»t f forehead

ciput) VA_ i //nostril

i I K, ’' lesser covert

[j '‘fore-neck
median coverts

greater coverts

rump {uropygtum)-

nppea'-tall coverts,. >

- secondaries

belly {abdomen)

^,outer or 4th toe

^ hind-toe-

' ‘under tail-coverts and'
vent

Fig. 1 79. —A Falcon. The regions of a bird's body.

The hen-pigeon lays two white eggs, which are sat upon
by the parents for fourteen days and thereby kept at a

THE PIGEON

273

temperature of about 40 degrees Centigrade. The young
birds then break through the shell and are hatched. As the
chicks are at first quite helpless apd unable to feed them-
selves, the parents supply them with a milky fluid secreted
by their crops. This is sometimes called / “ pigeon’s milk.”
Newly hatched pigeons are covered with fine feathers called
down, which are pushed off by the development of the
permanent feathers beneath them. The nests of wood-

Fig. iSo. -Wood-pigeon’s nest.

pigeons (Fig. t8o) are usually built in trees ; they are some-
what rough structures, composed of twigs, and open at
the top.

The wings. — A bird’s wings are full of interest, from
whatever point of view they are considered. Even now, the
exact manner in which they and the tail are used to bring
about the many different movements of flight is not fully
understood ; but a general idea may be obtained by an
examination of the bones and feathers and the careful
observation of flying birds.

N.S. S

274

AN INTRODUCTION TO NATURE-STUDY

The bones of the fore-limb and the neighbouring regions
show a remarkable modification of the primhive plan. The
bones of the upper arm OA, (Fig. i8i) and forearm {jRd.,
U/.,) are arranged much like the corresponding bones of
the rabbit ; but those of the wrist and hand are unlike any-
thing we have yet ex-
amined. The fourth
and fifth fingers have
entirely disappeared ;
and the first (thumb),
second, and third,
though they can be
still recognised (Figs.

184a),

have become consoli-
dated with what re-
mains of the wrist
(//^, yI///)toforma
firm mass which is in
no danger of “giving”
during the powerful
down-stroke of the
wing. The head of the
bone of the upper arm
fits into a socket
Fig. 182) at the junction of the shoulder-blade (scp.) and
another and stouter bone (cor,) which runs back and is
attached to the breast-bone or sternum (st). The sternum
in its turn is connected by means of ribs with the
spinal column, which is strengthened here by the fusion
of some of its bones. The ventral part of the sternum is
produced into a large plate called the keel [car.^ Fig. 182),
which gives attachment to the great muscles of the breast,
used in the movements of the wings. So great is the

Fifi. i8i.*-The skelefon of the limbs and tail of
a flying-bird. OA^ bone of upper arm ; OS^ bone
of upper leg ; Kd, Ul, bones of foie-arm ; 7’, /'/,
bones of leg ; //ff'', MH, bone-, of wrist ; F, F, F,
bones of lingers ; Z, Z, Z\ M 1\ bones of foot ; Scp^
shoulder blade ; Cr, keel on sternum (.S7) ; ]^g,
ploughshare bone.

THE PIGEON

275

development of these muscles in flying birds that in the
pigeon they have a weight equal to one-fifth the total
weight of* the body. The three* segments of the wing,
corresponding to the upper-arm, lore-arm, and wrist and
hand respectively are, in the position ol^ rest, bent upon
each other like the letter Z. The large quill feathers of the
wing, fixed along the hinder border of the limb, are in two
series (Fig. 179). Those attached to the fore-arm are called

Fig. 182. —Pigeon, The bones of the trunk, actfi, socket for bone of
upper leg ; car, keel of sternum ; ai.zf, vertebrae of tail ; cor, coracoid ;

Jur, menythought ; gl.c 7 j, socket foi bone of upper arm ; plough-

share bone ; sep, shoulder blade ; s.s(r, fused veitebrae of hip region ; st,
sternum; st.r, vr.r, rib; tJi.v.i, first, and //t.r’.s, last thoracic vertebra.

(xi.)

secondaries \ while those attached to the wrist and hand are
known as prwiaries. A smaller tuft of feathers borne by the
thumb is called the bastard-wing or fhtimb- 7 vi?ig. 'JTe
smaller feathers covering the bases of the wing-quills are
called wing-coverts.

The hind-limbs and tail. — The hind-limbs, or legs, of
birds are the sole support of the body except during flight,
and a relatively great weight is thus thrown upon them. To
provide for this, the skeleton of the hip region is excep-
tionally strong. Not only are the bones of the spine here
welded together into one solid mass, but the hip-bones

276 AN INTRODUCTION TO NATURE-STUDY

extend forward much further than is the caso in quadrupeds,
and are firmly attached to the fused vertebrae. Each hip-
bone possesses a socVtiJ {actk^ Fig. 182) into which fits the
head of the bone of the upper leg. Another fusion of bones
is to be noticed at the end of the tail, resulting in the
ploughshare-hone (Fig. 182, st.) which supports the large
steering feathers of the tail. The quills of these feathers are
covered at their bases by the tail-coverts.

Just above the end of the tail of a plucked pigeon is to be
seen a small conical body, the oil-gland., from which the
bird obtains a fluid which it applies to the feathers during
the preening process.

The featherif.—Feathers do not grow upon all parts of a
bird’s body, but are restricted to certain definite areas or
'‘^feather tracts ” which, howeyer,
differ in arrangement in different
species.

One of the large feathers of
the wing of the pigeon is illus-
trated in Fig. 183, A. It consists
of a hollow, horny quill {cal.\
prolonged into a solid shaft (rchl)
which supports the web or vane.
The outer face of the feather
is slightly convex and smooth ;
while the inner surface is some-
what concave and rough, and
carries a little tuft of down at the
junction of quill and shaft. The
growing feather is nourished by a conical projection of the
deeper part of the skin, which fits into a small hole (jnf
umh.) at the base of the quill. It is easily shown that the
vane of the feather is composed, on each side, of a large
number of parallel laths which spring from the shafh

Fig. 183. — Pigeon. A, portion
of a wing feather ; c«/, quill ; rch,
shaft ; iS, filoplume ; C, nestling-
down.

THE PIGEON

277

These laths ari^ called barbs. Considerable resistance is
felt when an attempt is made to pull the barbs apart, but
the manner^ of their connection canribt be clearly seen without
the aid of the microscope. A fairly low magnifying p6wer,
however, shows (Fig. 184) that each barb bears extremely
delicate threads — barbules — on
each side, arranged on the barb
much as the barbs are arranged
on the shaft. The barbules on
one side of each barb (the side
furthest from the quill) are seen to
carry tiny hooks) while the barbules
of the other side of the barb
are furnished with flanges. The
hooked barbules of one -barb cross
the flanged barbules of the next
and interlock with them ; so that
relatively great force is required to
pull the barbs apart and destroy
the continuity of the web. The
quill-feathers of the tail, and the coverts, have webs of
similar structure.

The contour-feathers are used for protection and warmth
rather than for flight, and hence have less -perfectly inter-
locking barbs. The hair-like structures seen on the skin of
the plucked bird are extremely simple feathers called mo-
plumes (Fig. 183, B). Each consists of a long, slender
axis, bearing at the end a few barbs which do not inter-
lock.

The down-feathers' (Fig. 183, C), which form the tem-
porary covering of nestling pigeons, also bear barbs which
do not interlock.

At regular intervals, either once or twice a year, birds
moult, that is, shed most or all of their feathers and grow

Fig. 184. — Structure of a
Feather, A, small portion of a
feather with pieces of two barbs,
each having to the left three
hooked barbules, and to the right
a number of flanged barbules ;
if, booklet of one barbule inter-
locking with flange of another
barbule ; C, two adjacent flanged
barbules ; I), a hooked barbule.
(After Pycraft.)

278 AN INTRODUCTION TO NATURE-STUDY

new ones. I’he moulting usually takes plafe gradually and
symmetrically : a flight feather from each wing, for example,
being dropped at the same time.

Flight. — The outstretched wing of a pigeon has a
relatively great area ; and is markedly convex on the upper
surface and concave on the lower, resembling in this respect
an open umbrella. The great difference in the resistance
which the inside and outside of an open umbrella respectively
oppose to the wind is familiar to everyone, and illustrates
the advantage of the dome-shape of the outstretched wing.
The force which the great breast- muscles put into the down-
stroke of the wing is enormous in comparison with the
weight of the body, and is sufficient to push the bird up-
wards and forwards in the air. The gently tapering shape
and smooth surface of the feathered bird diminish the
resistance of the air. When the wing is raised again for the
next stroke, the quill -feathers are turned a little edgewife,
so that the air slips between them ; just as an oarsman
“ feathers ” his oar to lessen the resistance to the blade in
the return-stroke. 'The direction of the wing-stroke can be
altered in accordance with the direction of air currents,
and the fan of tail-feathers is capable of being opened
or closed, raised or lowered, and turned at various angles
to act as a rudder.

But the method of flight which perhaps most of all excites
the observer’s admiration is soaring, in which the bird seems
to remain almost passive, with outstretched wings and
spread tail, and mounts automatically in a spiral course.
Exactly how the soaring is performed, only the birds them-
selves know ; but it must be similar in essence to the
arrangement of the sails of a yacht so as to select that com-
ponent of the force of the breeze which will drive the boat
in the required direction, even though this be almost “in
the teeth of the wind.” Such spiral soaring may be seen to

THE PIGEON

279

perfection, among common British birds, in the skylark (p.
316). A breeze is necessary for soaring.

In hovering, the motion of the ^ings is extremely rapid,
and the bird remains poised in one pl^ce. The kestrel
(p. 330) derives its common name of “wind-hover” from
its habit of using this method of flight when looking for
food.

The pigeon’s air supply. — We know that a man breathes
more quickly when he is taking active exercise than at
ordinary times ; and we might, from this and similar obser-
vations, expect to find the most perfect breathing organs in
animals which lead the most active lives. Of all vertebrate
animals, birds probably perform the most wo»k in proportion
to their size; and it is not surprising, therefore, to learn that
they have special facilities for quickly replacing fouled air
by fresh.

The lungs are comparatively small, , but they are not the
only organs of respiration (p. 242) ; for the windpipe opens
also into several air-sacs, which supply nearly all parts of the
body with air, and even communicate with the interior of
certain bones. The bone of the pigeon’s upper-arm, for
example, is hollow and contains air. By means of the
system of air-sacs, the air in the lungs is cofnplctely renewed
at each respiratory act, and thus the waste carbon-dioxide
in the blood can be exchanged for fresh oxygen much more
completely than it is in mammals. One result of this is
that the blood of birds is much warmer than that of
mammals. The air-sacs are also an assistance to flight by
rendering the body more buoyant.

Different breeds of pigeons. — The various breeds of
domestic pigeons furnish one of the best examph^s of the
changes in structure which breeders can bring abouh^t^
several generations, by careful crossing. In spite of the
great differences between, say, the tumbler, with its habit of

28o

AN INTRODUCTION TO NATURE-STUDY

turning head-over-heels in the air; the ^pouter, with its
exaggerated crop; the Jacobin, with its neck-feathers reversed ;
the fantall, with its large number of erect tail-feathers ; and
others, — there cap be no doubt that all these varieties have
been artificially produced from the rock-pigeon ; and it is
curious to observe occasional reversions to the characters of
the ancestral stock. “ The rock-pigeon is of a slaty blue,
with white loins. . . . The tail has a terminal dark bar,
with the outef feathers externally edged at the base with
white. The wings have two black bars. Some semi-
domestic breeds, and some truly wild breeds, have, besides
the two black bars, the wings chequered with black. These
several marks do not occur together in any other species of
the whole family. Now, in every one of the domestic
breeds, taking thoroughly well-bred birds, all the above
marks, even to the white edging of the outer tail-feathers,
sometimes concur pfrfectly developed. Moreover, when
two birds belonging to two or more distinct breeds are
crossed, none of which are blue or have any of the above-
specified marks, the mongrel offspring are very apt suddenly
to acquire these characters.” ^ This is a striking instance of
the, tendency exhibited by living things to revert to ancestral
characters, even though these latter may have lain dormant
for hundreds of generations.

EXERCISES ON CHAPTER XV.

1. Why does a bird require a long neck, and a keel upon the breast

bone? (1898)

2. Draw the bones of a bird’s wing, and mark the places of insertion

of the largest quills. (1898)

3. What bones carry the primary and secondary quills of a bird's
wing, and the quills of the tail ? Illustrate your answer by a drawing.

(1901)

* Darwin, TAe Origin of Species (Murray). Cheap edition, is

EXERCISES ON CHAPTER XV.

281

4. Point out* th^ chief differences between the skulls of a quadruped

and a bird. (1901)

5. Describe one of the large feathers o 5 a bird’s wing, (1898)

6. Draw general plans of the fore-limts of a mammal and a bird.

Letter the principal bones, so as to show how tHey correspond in the
two animals. (1901)

7. If the skull of 'a bird were placed before you, what features would

enable you to recognise it with certainty? (1901)

8. How does the fact that a bird stands on two leg^ affect the skeleton

of the trunk? (1897)

Fig. 184/1. — Comparison of Bat and Bird.

9. Point out the chief differences between the wing of a bird and tnat

of a bat. •

10. Explain how the barbs of a quill feather are attached to one

another. Describe a feather at the time when it is forcing its way
through the skin. (1905)

11. What peculiarities distinguish feathers which aid in flight from

feathers which merely prevent loss of heat? (1906)

12. Describe the wing of a bird, both as to skeleton and as to external

appearance. Compare the skeletal parts with those of the corresponding
structures in a Mammal. (1908)

CHAPTER XVI.

THE DEVELOPMENT AND EDUCATION OF THE
CHICK.

52. A HEN’S EGG.

Obtain three or four hen’s-eggs, and make the following
observations upon them :

1. External appearance. —What is the colour of the egg ? What
is its shape‘s. How doe;5 the shape differ from that of a cricket
ball or other sphere ? The shape of an egg is said to be ovoid.
[What is the difference between an ovoid and an oval ?] Measure,
with a tape, the length and breadth of the egg, and also its
distance round, (i) in the direction of its greatest length, (ii) in
the direction of its greatest width. What advantages has this
shape ? Could a hen sit so comfortably upon her eggs if they
had sharp corners ? Put an egg upon the table and roll it
gently. Does it roll in a straight line? Does it roll far before
coming to rest? Compare the rolling of a cricket ball or other
sphere. Is it an advantage that an egg is not likely to roll far,
or in a straight line ? Why ?

2. The strength of the shell.— Hold an egg with your thumb at
one end and your first or second finger at the other, and press
exactly in the line of the length of the egg. You cannot break
the shell.

3. Stmcture, — {a) The shell, — Tap the egg gently at the middle
of its broad end until the shell cracks. Then carefully remove
small pieces of the shell and notice the shell-jncmhranc^ a tough
skill which is closely applied to the inside of the shell. Snip

A HEN’S EGG

283

through the mer^brane in the middle of the broad end ; notice the
air-chai 7 tber which lies beneath it. Observe the inner membrane
which separates the air-chamber fi*om the inside of the egg.
Hold a piece of shell up to the li^ht, and notice the small,
almost transparent dots. The shell is perfcA-ated by very small
pores, through which the air can pass.

{b) The white of the c^^.~Tap the shell so as to crack it all
round at its widest part ; raise bits of shell carefully and see the
membrane here. Tear through the membrane and notice that
in this region there is no air-space, but the white lies just
beneath the shell-membrane. Separate the halves of the shell,
notice the position and shape of the yolk, and then let the
contents of the egg hill gently into a basin. Observe the
appearance, colour, and transparency of the ndiite, and try
to distinguish two tangled cords of firmer white — the balancers
(Fig. 185)— arising close to the yellow yolk.

(c) The yolk. —What is the shape of the yolk as it lies in the
basin ? How does it differ from the shape of a yolk suspended
naturally in the white? What is the ^ause of the change of
shape? Notice carefully a small paler patch in the middle of
the upper surface. • This is the lightest part of the yolk, so that
the yolk always settles with this part uppermost after any
turning of the egg, and therefore the pale patch is always
more directly exposed to the heat of the hen’s body (during
incubation) than is any other part of the yolk. Prick the yolk
and notice that the yellow, fluid contents flow out. You have
evidently pierced the thin bag which formerly preserved the
shape.

(d) A hard-boiled egg . — Boil an egg in water for five minutes,
and then chip round the shell in the direction of the length and,
with a sharp knife, cut the whole egg into halves along this
plane. Make a drawing of the section, indicating the shell,
shell-membrane, air-chamber, white, and yolk in position.
Observe that the white is no longer transparent and fluid, but
an opaque, white, and elastic solid. Try to peel off the white in
layers. They* will probably break off short, but you may be able
to see that the white is deposited in spiral sheets around the
yolk.

284 an introduction TO NATURE-STUDY

Tlie hen’s egg. — A hen’s egg bears a sopewhat similar
relation to the adult bird that the maize or bean seed
(Chapter 1 .) bears to the 'adult plant ; for the eg^ contains

(1) a spebk of living ’matter which little by little grows
and becomes marked off, by orderly arrangement, to form
the various regions and organs of the adult animal ; and

(2) a store of food, which enables the young chick to
develop in security, without being hampered, whilst still
weak and helpless, by the necessity of earning its own
living. The changes by which the speck of living matter
becomes the perfect chick will be considered in the next
section. We must now examine the structure of the egg
itself, and see what provision it contains for the nourish-
ment and safety of the developing bird.

The egg is ovoid in shape, one end being distinctly
broader than the other. This shape has the advantage of
preventing the egg from rolling very far when placed upon a
slightly inclined surface, and it is worthy of notice that the
eggs of birds which lay on cliffs and other ^exposed situations
are usually more elongated and pointed than others, so that
when stirred they do not roll away, but simply describe
a small circle and come to rest again. In the case of eggs
which are laid in cup-shaped nests (Fig. 197) the pear-shape
lends itself to close packing, and thus allows the eggs to
be more easily kept warm by the parent bird.

The shell {sh.^ Fig. 185) is composed of a chalky material,
and is perforated by small pores, through which the
developing chick obtains fresh oxygen from the air, and
gives off its surplus carbon dioxide (p. 242). A small piece
of shell easily snaps, but the shape of the complete shell so
distributes an outside pressure, especially one in the direc-
tion of the long axis, that relatively great for^e is required
to break it. The shell is lined by a thin, parchment-like
membrane {sh. m.). At the broad end of the egg this

A HEN’S EGG , 285

membrane is cjouble, and the two layers enclose an air-
chamber (a).

Inside the shell-membrane are the white or albumin, and
the yolk. The white (aid'.) is a viscous, ^transparent fluid.
Its innermost part (a 3 .\ which immediately surrounds the
yolk, is of thicker consistency than the rest, and is pro-
longed into two twisted cords called the balancers {ck.)^
which suspend the yolk in position.

Fig. 185 — Semi-diagramimtic view of a fowl s egg at the time of
laying a, air space , dense 1 lyer of albumin , , more fluid

albumin , di, germinal disc , c/t, balancers , y/z, shell ik M, shell-mem
brane , jrA m i, sh m 2, its two layers separated to enclose air spice ,
yk, >olk (After Marshall ) (Xi )

The yolk is a golden-yellow fluid enclosed in a thin,
elastic membrane and hence preserving a spherical shape.
On its upper surface (but under the membrane) is a small
circular patch {bl.) of paler colour. This patch, called the
germinal disc, is about in diameter ; it contains the living
matter from which the chick will be formed ; the rest of the
yolk, and the white, are simply a store of inert food which is
used up by the growing chick.

The work of the balancers. — In order that the small
living patch of pale yolk, the germinal disc, may grow and

286

AN INTRODUCTION TO NATURE-STUDY

develop into the chick it must be kept warip. When eggs
are hatched in the natural manner, the heat is supplied by
the body of the sitting hen, and the upper part of the egg is
consequently kept warmer than the rest. It is important
that the living part of the egg shall always lie nearest the
hen’s body and thus be kept warm, and this is secured
by an arrangement as effective as it is simple. The yolk
is lightest in the neighbourhood of the germinal disc,
and therefore always lies with this part uppermost. If the
egg is slowly turned over, the yolk remains “ right side up.”
If it is turned over quickly, the yolk soon swings rounddnto
its original position. 'The twisted cords of white, the
balancers, not f only sling up the yolk and guard it from
being thrown to one side by a sudden movement, but they
also prevent it from rotating too quickly — and so possibly
injuring the delicate body of the young chick —when it
rights itself after the pgg has been turned over.

The balancers are rendered necessary by the hen’s habit
of turning her eggs two or three times "'a day. It is often
supposed that the eggs are turned in order to keep them
equally warm on all sides, but this is unnecessary. Most
probably the egg is turned in order to alter slightly the
young chick’s position from time to time, and allow its parts
to grow naturally, unimpeded by the other contents of the
<^gg-

53. THE DEVELOPMENT OF THE CHICK.

I. A simple incubator. — Eggs are best incubated in the natural
manner, that is, by the warmth of the hen’s body ; but if a sitting
hen cannot be obtained, an ordinary water-oven, such as is used
in chemical laboratories, may be made to answer. It should be
heated by a self-regulating burner, and kept at a temperature of
about 40° C. The eggs should be turned two or three times a
day, and the air of the oven should be kept moist by sprinkling
water upon pieces of cloth, blotting paper, or hay, kept with the

DEVELOPMENT OF THE CHICK

287

eggs. Spring is the most favourable time of the year for
making the observations, as eggs laid at other seasons are not
always in condition to produce chic^ks.

2. How to mark the eggs, — The most instructive changes take
place during the first five days of incubatiot^ If all the stages
of the first five days are to form the subject of one lesson, an egg
should be marked “ 5 ” with pencil, and then put into the
incubator or under the hen five days before the lesson ; a day
later, an egg numbered “ 4 ” should be put in, and so on. The
numbers will then indicate the length of incubation at the time
of the lesson, and the eggs should be examined in order, from i
to 5. If one egg is to be examined each day, five should be put
in the incubator at the same time ; no numbering will then be
required.

3. How to examine the eggs. — Have ready ai basin of water,
heated slightly above the tcmperatuic of the hand {i.e. to about
40“ C.), and dissolve table-salt in it in the proportion of a level
teaspoonful of salt to a pint of water. The young chicks will
keep alive longer in this solution than m ordinary water. Tap
the shell in the middle of its broad eftd, and open the air-
chamber (cz, Fig. 185) completely. Then crack the shell in the
middle of the length and, keeping the length of the egg
horizontal, cut transversely round the middle of the shell with
scissors in a vertical plane, until the halves are on the point
of coming apart. Then lower the egg into the warm saline
solution, pull the halves of the shell apart, and float out the
contents. Examine the embryo carefully, making out as much
as possible, and then snip round it with a pair of fine scissors
to remove it from the yolk ; float it into a watch-glass and
cover it "with weak alcohol (equal parts of Water and spirits
of wine). Examine it with a lens. After it has remained for
a day in weak alcohol, put the embryo into strong alcohol
in a small bottle (writing the age on a label), and preserve it.

Notice the gradual absorption of the white of the egg as
development proceeds.

4. CMck after one day’s incubation. — Notice that the embryo
is now to be distinguished as a streak crossing the germinal
disc in a direction at right angles to the long axis of The

m AN INTROPUCrrON TO NATURE-STUDX

egg. Notice a rounded swelling at one end of the embryo;
this is the head. Place the egg before you with* the broad end tO
your left, and observe that the head of the embryo points away
froth you.

5. Chick after two days* incubation. — Observe the increase in
size of the embryo ; make a note of its length. The head and
neck of the embryo are now almost covered by a very* thin trans-
parent bag which has grown over it from the sides. This bag is
called the amnion ; it is filled with fluid, and protects the
embryo from jars. Remove the amnion and notice the large
head ; it is now twisted so that its left side lies against the yolk,
while the rest of the embryo still lies ‘‘ face-down.” Observe the
large eye on the right side of the head ; the left eye cannot be
seen without turning the head over. Notice the hearty a sfnall
red dot which by help of a lens can be seen to beat rapidly.
Surrounding the embryo is a circular netwoik bf blood-vessels
which bring food from the yolk to the heart* to be distributed
to the various parts of the body. How large is the circular area
of blood-vessels ?

6. Chick after three ^kya* incubation. — The white of thp egg is
distinctly shrunken, and the network of blood-vessels is much
larger than before. Remove the amnion and notice the
marked increase in size of the embryo, especially of the head.
The right side of the head and neck are still turned to-
wards the shell. They are now quite free from the yolk, but
the body of the embryo communicates with the yolk by a short,
wide tube, the yolk-stalk. Try to see a small pit, a little above
and behind the large eye. This is the beginning of the right ear.
Measure the embryo and the width of the surrounding network of
blood-vessels. Watch, through a lens, the beating .pf the heart

7. Chick after four days’ incubatioxL— Carefully cut open the
amnion to see the embryo better. Observe that the young
chick is still more completely folded off from the yolk, and that;
the yolk-stalk is consequently narrower than before. The head
is so strongly bent upon itself that the snout almost touches
the tail. The body also has now turned over so as

with its left side on the yolk. Observe the two pairs of s All
bills which are the rudiments of the iimbs*^

DEVELOPMENT OF THE CHICK 289

8. Cbick after five days* incalmtloxL — Cut open the amnion^ and
notice the greai increase in size of the embryo, and especially
the enormous development of the head. The limbs now show
signs of division into segments. Observe, under the hinder end
of the body, a small, bladderdike outgrowth, the allantois.^
which in the later stages grows rapidly and spreads all round
the inside’of the shell. It is the breathing organ of the chick.

9. Effect of varnishing an egg. — Varnish an egg, and leave
it under the hen with unvarnished eggs for the whole period of
incubation (21 days). The varnished egg does not develop,
because the varnish closes the pores of the shell and prevents
the ‘embryo from breathing.

The early development of the chick. — When the hen's
egg is exposed to a temperature of about 40 “C., the germinal
disc — the cirdular patch of living matter which lies, somewhat
like a small inverted watch-glass, upon the upper surface of

^ Fig, 186.— Hen’s Egg after i day’s incubation. «, .tti -chamber ; hti^
head of embryo ; z' a,, area in which yolk blood-vessels will appear later ;
yolk, (xi.)

the yolk — grows larger, and its parts are gradually modified to
form the various regions of the chick’s body. The white and
yolk of the egg are used up during the process, and by the time
tliey absorbed/ the young bird is in a condition to Break

290

AN INTRODUCTION TO NATURE-STUDY

the shell and take up the activities of an independent life. To
watch the orderly appearance and gradual development of
the different systems of organs is most fascinating, and for-
tunately the observation of the main features presents no
great difficulty if the foregoing instructions are followed.

The first signs of the chick are to be seen (Fig. 186),
towards the end of the first day of incubation, in a streak
which crosses the germinal disc in a direction at right
angles to the long axis of the egg. One end of the streak is
distinctly rounded, and this is the head end {hd.). In almost
all cases, if the egg be placed so that its broad end is to the
observer’s left, the head of the embryo will be directed away
from him.

A day later, tKe embryo is markedly larger, and is partly
covered by a double membrane called the amnion.^ Sur-
rounding the embryo is now (Fig. 188) a network of fine

^ The amnion originatesip early in the second day, as a double fold of
the yolk-surface in front of the embryo. Similar folds arise round the

A />’ C

Fig. 187. — Diagrams to illustrate the method ot development of the
amnion. The embryo and the rest of the yolk are supposed to be seen
in median longitudinal section ; the head end is to the right. For con-
venience, the yolk-memhrane {yk.m.) is represented at some distance
from its contents, am, folds of amnion; nni.c,, amniotic cavity; em'
embryo ; yk, yolk ; yk.st., yolk-stalk. (After Foster and Balfour.)

sides and tail, forming a low wall (Fig. 187, ^) ; the folds gradually
grow over the embryo (Fig. 187, B) until, during the fourth day, they
meet (Fig. 187, C) and enclose it in a protective transparent bag, con-
taining a watery fluid.

DEVELOPMENT OF THE CHICK

291

blood-vessels which ramify over the yolk and carry small
particles of yolk to feed the growing organs. At the end of
the second day the network couid be about covered by a
sixpenny piece. On each side, its veins join to form a single
small tube running to the heart {/if.), a tifty red dot which is
situated behind the head and can be seen, by the help of a
lens, to be beating rapidly. The head has grown more than
the rest of the embryo, owing to the rapid development of

the primitive brain, and is bent forwards. The head has
turned over a little, so that its right side is directed towards
the egg-shell; the rest of the embryo still lies “face down.’'
The right eye (e.) can easily be seen as a dark spot on the
side of the head.

By the end of the third day (Fig. 189) the head and neck
are raised distinctly above the yolk, and the tail is also more
plainly markpd off, so that the body is connected with the
yolk only by a short wide tube, the yolk- stalk {y/i.-si.. Fig.
187, B). The neck as well as the head has now turned

2^Z

AN INTRODUCTION TO NATURE-STUDY

so as to lie with the right side directed towards the shell.
The commencement of the ear is to be seen on each side as
a small pit (au.) a little above and behind the large eye.

Fig. 189. — Hen’s Kgg after 3 days’ incubation. The amnion has been
removed. References as in Fig. 188. (xi.)

^ On the fourtn day the embryo turns to lie entirely on its
left side. It becomes more completely folded off from the
, yolk, and the connecting yolk-stalk

is a narrower tube than before.
The previously formed organs in-
crease in size and complexity. The
disproportionate size of the head,
owing to the great development of

Fig, 190.— Chick Embryo
after 4 days’ incubation. The
amnion has been removed,
rt//, allantois ; am, cut edge of
amnion ; /.Z, fore-limb ; h.i.,
bind-limb ; kt, heart ; t, tail.
(After Duval.) (X2.)

the brain, is still more marked than
before, and the head is so strongly
bent upon itself that the snout almost
touches the tail. One of the most
noteworthy features of the fourth day

is the appearance of the limbs. As yet these, are merely a

pair of small buds (yf., ///., Fig. 190), and no joints can be

detected in them.

DEVELOPMENT OF THE CHICK

293

By the end of the fifth day (Fig. 19 1) the head is enormous,
and the limbs now show signs of being divided into definite
segments.* A thin bladder-like stracture— the allantois (a//.)y

Fig. 191. — Hen’s. Egg after 5 days’ incubation, a, air-chamber; ali^
allantois; am^ amnion; ar.vasc.^ area of volk blood-vessels; emby
embryo ; yolk. (Alter Duval.) (xi.) •

which appeared on the fourth day — has grown out from the
lower part of the body, behind the yolk-stalk. Its mode of
origin is well shown in
Fig. 192. It rapidly in-
creases in size, and soon
extends over the embryo
(Figs. 192 B, and 191)
and becomes closely
applied to the shell
membrane. Air passes
through the pores of the
shell, and its oxygen is
taken up by the blood which circulates in the vessels of
the allantois. At the same time, waste carbon dioxide is
able to escape from the blood to the outer air. The allantois

Fig. ig2.— Diagrams illustrating the method
of development of the allantois, a/, allantois ;
am, amnion fold ; atn.c , amniotic cavity ;
embryo ; yk, yolk. (After Fos*«!r and Balfour.)

294

AN INTRODUCTION TO NATURE-STUDY

is therefore the breathing organ of the developing chick. If
the egg is varnished and the shell thus rendered air-tight,
the embryo dies of suffocation at an early stage.

The chief organs of the bird are now established, and the
later development may be sketched more briefly. By the
end of the ninth day (Fig. 193) the white
of the egg is almost used up ; the yolk,
bpwever, is still large, and is connected
with the chick^s body by the narrow yolk-
stalk. It thus appears that the white is
not directly absorbed by the chick, but is
first taken up by the yolk and afterwards
Fig. 193.— Chick after passed on by the yolk blood-vessels which

9 days’ incubation. (Af- , , i

terJDuvai.) (xi.) run to the heart. By this time, too, the
allantois has spread at least halfway round
the inside of the shell, that a supply of oxygen adequate to
the increased needs of the animal may be obtained from the
air.' The chick has now a characteristic bird-like appearance;
the beak has appeared ; feathers have begun to sprout ; the
neck is long and slender; and the segments of the limbs,
including the fingers and toes, are well defined.

About the fourteenth day the chick turns so as to lie
lengthwise in the shell, with its head near the broad end.
The yolk-sac dwindles in size, and at last, about the twentieth
day, it is drawn into the interior of the body. Now the chick
becomes restless, and — usually on the twenty-first day —
thrusts its beak through the inner shell-membrane into the
air-chamber at the broad end of the egg. For the first time
it draws refreshing air into its lungs, and is stimulated to
break the shell by a knob on its beak, and to creep out
into the world.

EARLY LIFE OF THE CHICK

29S

64. THE EDUbATION AND LATEE GROWTH OF THE
• CHICK.’.

1. Hatching. — On the 20th or 21st day of incubation remove
three or four eggs from the clutch undef the hen, and keep
them in a warm cosy place so that you may watch the process of
hatching. Can you hear the chick tapping the inside of the
shell ? Could it have been tauf^ht to tap 1 Which part of the
shell cracks first ? When the shell has cracked, can you hear
the chick chirping? Could it have been taught to chirp?
Imitate the chirp and listen for a response. Keep the newly-
hatched chicks in a warm, soft place. How soon do they
recover from the exhaustion of hatching? Do the chicks show
a liking for warm corners ? Are they afraid ^f being touched
gently ?

2. Locomotion. — How soon do the chicks begin to run about ?
Do they stumble upon obstacles, or do they avoid or leap over
them ? Do they use their wings in running, or in jumping down
a small step ? Put a chick into a basket, and lower the basket
quickly through the air, being careful not to let the chick fall
out. Does it move its wings ? How?

3. Feeding and drinking. — Lay a few grains of soaked wheat
upon the ground before a chtek which has not yet been fed.
Does it peck at them instinctively? Tap a grain with the point
of a pencil ; does the chick now peck at it ? Does it hit the
grain at the first try? Does it ever strike at a grain which is
out of reach ? Watch a hen with hci chicks ; does she teach
them to peck at food? How? Do the chicks know instinc-
tively the difference between food and grains of sand, or have
they to learn ? Try if a chick can distinguish between a small
worm and a bit of red worsted. Are young chicks afraid of
large insects ?

Take a chick, which has not yet drunk, to a small pool (a few
drops) of water? Does it seem to know the use of the water?
Induce it to peck at the water ; does it now drink? How?

^ I desire to acknowledge my indebtedness, in drawing up this sec-
tion, to Prof. Lloyd Morgan’s Habit and Instinct (Arnold).

296 AN INTRODUCTION TO NATURE-STUDY

4. The crouchln^-instinct — Clap your hands suddenly and
loudly near young chicks. How do the chicks* behave ? Does
this behaviour render theni less conspicuous ?

5. Non-recognition of heyi. — Having made the above observa-
tions on chicks hatched apart from the hen, put the chicks
among their brothers and sisters with the parent hen. Do the
new-comers respond, as readily as the others, to the clucking,
etc., of the hen ?

6. Maternal training and protection. — How many different
meanings can you recognise in the different sounds of the hen’s
voice ? How does she call and protect the chicks when any
danger threatens them ?

7. The voice of the chick. — Notice the different sounds by which
a chick expresses pleasure, alarm, distress, etc.

8. Preening an<J^ scratching. — At what age do chickens begin to
preen their feathers, and to scratch the ground? Try to dis-
cover if these are instinctive activities, or whether they have to
be learnt from the hen.

9. Change in plumage. — At what age are the down feathers
replaced by the true plumage ? At what age is it possible to
distinguish the young cocks from the young hens ?

10. External characters, etc., of adults. — Notice the flowing
tail-feathers, hackles (the long feathers on the neck and loins),
comb, and spurs of the cock-birds, and their absence or small
size in the hens. What differences are there as regards voice ?
How does the hen announce that she has laid an egg ? Which
sex is the more pugnacious ?

The recently hatched chick. — The newly-hatched chick is
clothed with fine down-feathers (pp. 273 and 277). It is
generally exhausted by its struggles to escape from the shell,
but it soon recovers, and is able to run about freely on
the second day after hatching. Young birds which, like
the chick, are active immediately after hatching, are said to
be precoclouSt

Instinct and education.-~From the first, the chick per-
forms certain movements which are obviously instinctive,

EARLY LIFE OF THE CHICK

297

that is, which have not been acquired by any process of
imitation or instruction. Even in the egg» it may be heard
chirping scfon after it has taken its first breath of air ; and
the complex activities of walking, running, jumping over
obstacles, and, later, preening the feathers end scratching the
ground — each of which involves the nicest adjustment of
several muscles — are also instinctive. Certain other powers
have to be learnt ; the hen, for example, lifts and drops
before the chick a particle of food which she wishes it to
seize, and it soon learns to peck. At first its pecks generally
fall a little short of the objects, but presently it becomes
very adroit at catching food. “A chick a day or so old will
catch a running fly at from the seventh to the twelfth shot.’* ^
There does not appear to be much instinctive recognition of
the difference between objects which are valuable as food
and those which are the reverse. Such discrimination comes
only by experience, and to a very young chick a piece of red
worsted and a small worm are equally Attractive before being
seized. In the same way, the nature of water has to be
learnt. Chicks peck at drops of water, but do not seem to
know the use of water until their beaks are wetted, w’hen
they drink instinctively in the usual manner.

The use of the wings is also a matter of instinct, but it is
acquired somewhat late, and is assisted by parental en-
couragement and example even in birds which are noted for
their powers of flight. Fowls do not fly much, but chicks
may be observed to use their wings as an aid in running or
jumping. Prof. Lloyd Morgan^ quotes an interesting experi-
ment which shows well how deeply the reliance on flight is
stamped in bird-nature. “ If a chick a day or two old be
placed in a basket, l>eld firmly in the hand, and then
lowered rapidly through the air, the fledgling will stretch out
his little immature wings in such an attitude as would make
^ Lloyd Morgan’s Habit and Instinct (Edward Arnold).

298 AN INTRODUCTION TO NATURE-STUDY

them break the fall were they fully developed ; or will, if he
be a little older, flap them with flight-like action, in either
case showing an instinctive response.” . *

Hens and chickens. ~ Chickens which have been hatched
in the natural ma«iner are, from the first, under the control
of the hen (Fig. 194), and her anxious care for their welfare
has always been considered one of the most beautiful
examples of the maternal instinct. In their defence her
courage is unbounded ; should she discover a succulent

worm or other dainty
morsel, her ordinary com-
placent cluck changes to
a note of invitation, to
which the brood at once
responds ; and at her
danger-signal the chickens
run to take refuge under
her wings, or crouch
motionless against the
ground. The chirp of a
chick also is capable of
expressing several states
of feeling, such as contentment, pleasure, alarm, and
distress. These different notes are not only perfectly
intelligible to the hen, but are familiar to anyone who
has had experience of poultry.

In the face of these well-knowm instances of the perfect
understanding between the hen and her chickens, it is
somewhat surprising to find that chickens, hatched apart
from the hen and then placed with the rest of the brood
after a few days, at first pay very little attention to the hen,
except for their instinctive tendency to nestle into warm
places, and do not seem to understand her clucks.

Adult fowls. — The down-feathers are soon shed and

Fig. 194. — Hen and Chickens.

ADULT FOWLS

299

replaced by thQ true plumage, and the chicken gradually
takes on the appearance of the adult. A marked difference
is generally to be* seen between fhe cocks and hens (Fig.
195) of any breed of poultry. The c p c-k Ls iisiia]l y--f»mvHled
with flowing tail- feathers, h ackle ^ (elongated feather s on the

Fig. 195. — Cock and Hens.

ne ^ and loin^ a p rominent ^ comb, and “ spurs ’’—features
wKidi are either absent or niuchless perfectly developed in
the hens. As great differences exist between the voices of
the two sexes, the crow by which the pugnacious male
challenges his rivals, and the cackle of the hen when she
has laid an egg, being familiar examples.

306

AN INTRODUCTION TO NATURE-STUDY

EXERCISES ON CHAPTER XVI.

1. Point out the differences in appearance and position between
the white and yolk of a fowl’s egg. What becomes of each during the
development of the egg ?

2. When does the heart of a chick begin to beat? Describe its
appearance at this time, and explain what must be done to expose it to
view.

3. Explain exactly where the chick is to be found in a fertile egg
which has been incubated for three days. Mow big Ls a chick of that
age? Of what coloui is it ? Does it give any signs of life? (1898)

4. What is the amnion ? Where, in a developing chick, is it to be
found, what is its appearance, when and how is it formed, and what is
its use ?

5. Explain the nature and use of the “ balancers ” of an egg.

6. Explain how a developing chick breathes.

7. What new organs are first seen distinctly on the fourth and fifth
days respectively of incubation of a hen’s egg ? Explain exactly how
you would expose them t# view, and describe their appearance.

8. What is the period of incubation of a duckjs egg? Observe and
describe exactly how the hatching duckling breaks open tfie shell and
escapes from it.

9. Observe and describe a duckling’s first attempt to swim. Is the
action instinctive or not ?

10. Make other observations upon ducklings, comparing them in as
many respects as possible with chicks, and write careful accounts of the
results you obtain.

11. How does a fowl’s egg which has been hatched for lour days
differ from a fresh-laid egg ? Describe the new structures which have
formed in it, so far as they can be made out by the unaided eye.

C1904)

12. Where docs the chick begin to form in the egg? Explain the

arrangement whicli brings it as near as possible to the body of the
sitting hen. * (1905)

13. What is the use of the cloudy masses attached to opposite sides of

the yolk of a fowl’s egg ? (1906)

CHAPTER XVIL

SOME FAMILIAR BRITISH BIRDS.

55. THE THRUSH FAMILY.

I. The song-thrush, mavis, or throstle. — Thri^stlcs" are to be
seen throughout the year. Take every opportunity of observing
their habits, and make careful notes of these at the time. Espe-
cially attend to the following characters :

(a) General appearance. — What is the average size of the
bird? What is the length of the tail? *At what angle is the
tail held? Does the. bird move it in any special manner? What
is the prevailing colour of the body ? Notice the light-coloured
and spotted breast. Compare the male and female as regards
size, colouration, etc.

Habits. — What situations do throstles chiefly inhabit ? Do
they keep near the edge of the wood, or have you often seen
them inside thick woods ? Does the bird hop, or walk, when on
the ground ? Upon what does it feed? Have you ever seen it
cracking the shell of a snail ? If you find a heap of snail-shells
near a stone, watch, at a little distance, for the throstle coming
to crack snail-shells on the stone. Does it also eat worms, or
fruit ? Describe a throstle’s beak. How would you describe
the flight — as high or low, swift or slow, straight, in wide curves,
or undulating ? Does the bird perch on trees ? How does it
use its toes in perching ?

{c) Song, — Ln what months does the throstle sing ? Does it
sing late at night and early in the morning ? How does it com-
pare with other birds in this respect ? In what positions have

302

an' INTRODUCTION TO NATURE-STUDY

you seen the bird singing — when flying, perching, or on the
ground? Try to write down the syllables which seem to you
most like the throstle’s so^g, and notice how the phrases are
repeated. Notice that throstles sing less during August than in
autumn. Listen, in September or October, for young thrushes
learning to sing, and contrast their efforts with the song of the
adult birds.

(if) The nest . — At what time of the year do throstles pair and
build their nests ? In what situations have you found the nests?
Write a description of the shape, size, and materials of the first
throstle’s nest you find. Visit it frequently, try not to disturb
the birds, and note the dates of laying of the eggs. How many
eggs are laid ? What are their size and colour ? How are
they arranged in the nest ? Do the broad or the narrow ends
point inw^ards ? r What are the advantages of this arrangement
(i) for purposes of packing, (ii) when the eggs hatch ? Do both
birds sit on the eggs ? If only one, which ? What is the time
of incubation ?

(c) The youn ^. — Are the young birds naked and helpless, or
feathered, at hatching^ How do the parent birds feed them?
What is the appearance of the fledglings ? In what respect do
they (i) resemble, (ii) differ from, the parents? How long do
the birds remain in the nest after hatching ? Write an account
of any education you have observed them to receive from the
parents.

[Make similar observations and notes on other birds, in
addition to the special observations mentioned below, and learn
to recognise their appearance, flight, song, nest, and eggs. A
field-glass will be found of great assistance.]

2. The missel-thrush, or storm-coclr. — Compare the missel-
thrush w'ith the song-thrush. Notice its larger size, the brighter
colour of its spotted breast, and its somewhat less musical song.
Listen for its song during, or immediately after, a storm, even
in winter. In the nesting season observe the marked courage
and pugnacity of the bird.

3. The blackbird. — Compare the blackbird with the thrushes in
respect of appearance, food, habits, and song. Notice the differ-
ence in the colouration of the male and female blackbird. Observe

THE THRUSH FAMILY

303

that the young bird has a spotted breast like that of a thrush,
but that old blackbirds are not spotted. Have you noticed a
blackbird shpw a preference for singing in any particular place ?
What observations would lead you to suppose that the blackbird
is a near relative of the thrushes ?

4. Fieldfares. — Distinguish these birds from* thrushes Notice
that they arrivp about October, and frequent fields in large
parties.

The thrush family. — For many reasons the thrush family
forms a convenient starting point in the study of the habits
of common British birds. It includes some of our very
finest songsters and therefore most popular birds ; many of
its members are abundant in most parts of the country, so
that nearly every student has the opportuni^ of observing
them at first hand; the birds are not s])ecially shy; and,
lastly, the family affords excellent material for the method of
comparison and contrast, which, be it repeated, is the
essence of all sound work in nature-study.

The song-thrush, y/hich is also known as the throstle and
mavis, is a shapely bird, easily recognisable by its grey, spotted
breast (Fig. 196), which may be seen all the year round in
wooded parts of the country. The male and female are very
similar in appearance, and of almost equal size, measur-
ing 8 or 9 inches from head to tail. The thrush generally
feeds on the ground, hopping along on a pair of sturdy legs
and feet, seizing and pulling out worms which incautiously
show themselves at the mouths of their burrows, and catch-
ing insects and snails. A thrush usually has a favourite
stone on which it cracks the shells of snails, and it is not
uncommon to find, near the stone, a little heap of broken
snail-shells — the remains of many a feast. In winter, when
the summer diet can no longer be obtained, the thrush
subsists largely upon the fruit of hawthorn, mistletoe, etc.
Its beak, as is usual with birds, is distinctly adapted to the

304 AN INTRODUCTION TO NATURE-STUDY

capture of its food, being, in this case, narrow, round, and
fairly long. The thrush is a strong and rather rapid flier.

Thrushes begin to sing at the first signs of spring, pairing
and commencing the 'Work of nest-building in February or
early March. The throstle’s song is surpassed by very few
birds ; and many people consider it equal, if not superior, to
the nightingale’s. The song begins before sunrise, and may
be heard when almost all other birds have retired to rest
The thrush has a curiou^ habit of repeating each strain two

Fig. 196.— Song-Thrush, (x i).

or three times, “lest,” as Browning says, “you should think
he never could recapture the first fine careless rapture.”
Many attempts have been made to imitate the song by
words ; Mr. R. Kearton ^ quotes with approval the following
rendering by the famous Scottish naturalist Macgillivray :

** Qui qui qui kweeu quip,

Tiurru tiurru chipiwi,

Too-tee, too-tee, chiu choo,

Chirri chirri chooee
Quiu qui qui.”

* Our Bird Friends (Cassell).

THE THRUSH FAMILY 305

But, as Mr. Kearton remarks, “ no human words can ever
represent, especially in cold type, the passionate vehemence,
the sprightfliness, or the tender pleading of a thrush’s song.”

The nest of the thrush (Fig. 197)* is a massive structure,
deep and cup-shaped, and open at the *top. It is built of
small twigs and grass, and is plastered with mud or cow-
dung until the inside is smooth and hard. It is usually

Fig. 197. — Nest of Song-Thrush. (X^).

placed in an evergreen bush or tree, but may also be found
in cavities in tree-trunks or in holes in walls, or even in
sheltered places on the ground. The eggs number from 4
to 6 ; they ate about an inch long, are sky-blue in colour,
and marked with black spots, which are most numerous
near the thick end. The eggs are arranged with their
pointed ends^ inwards ; this method not only allows them to
be packed more closely together and therefore to be more
easily covered by the sitting bird, but is also of convenience
N.S. U

306 AN INTRODUCTION TO NATURE-STUDY

at the time of hatching, as the young birds^ usually emerge
(p. 294) at the thick end. The eggs hatch after a fortnight’s
incubation. The young thrushes are at first blind, almost
naked, and are quite helpless. They make rapid progress,
however, and are '^sufficiently fledged to leave the nest in
about a fortnight after hatching. The fledgling throstle
(Fig/ 1 98) is lighter in colour than the adult, and much

Fig. 198. — Young Song-Thrushes in Nest.

more distinctly spotted. In October the young birds may
be heard learning to sing ; their first efforts are hesitating
and uncertain, but by tireless practice and careful imitation
of the old birds they presently come into full possession of
their delightful powers.

The missel, or mistletoe, thrush (Fig. 199) much resembles
the song-thrush in appearance and manner of life, but is
distinctly larger, measuring about loi inches from head to
tail. It has a very pleasing song, which may be heard, even
in the depth of winter, when all other song-birds are mute.

THE THRUSH FAMILY

307

The missel thr,ush’s habit of singing vigorously during
storms has led to its alternative name of “storm-cock.” The
bird is no^ed for its pug-
nacity in the breeding
season, and for the courage
with which it defends its
nest and young ; any other
birds approaching the nest
are promptly attacked and
driven to a distance. The
nest is generally built in a

tree, where a branch springs fig. igy.-Mistietoe-Thrush. (xl)
from the trunk It is made ^

of dried grass, moss, and wool, and the hen lays from 4 to 6
pale-green eggs, which are speckled with brown.

The blackbird (Fig. 200) may easily be distinguished from
the thrush by its colour — the male joeing black, with a

Fig. 200. — Blackbird (Hen), (xj.)

3o8 an introduction TO NATURE-STUDY

yellow beak, and the female blackish brown,, slightly mottled
below. The blackbird is slightly larger than the thrush, but
in shape and habits the'’ two birds are very sirAilar ; they
haunt the same woods, live upon similar food (i.e, worms,
insects, snails and,“ in winter, fruit) and build their nests in
similar situations. The blackbird’s song is, however, quite
distinctive, and consists of mellow, flute like notes, without

Fig. 201. — Blackbird’s Nest.

the repetition which is so characteristic of the throstle and
missel-thrush. The blackbird is fond of perching, when
singing, upon a bare branch which commands a good view
of the surroundings. The nest (Fig. 201) is much like that
of the song thrush, but the inside has a soft lining of fine
grass instead of being hardened with mud. . The 4, 5, or
occasionally 6 eggs are bluish-green in colour, and are
marked with blurred brown spots.

THE THRUSH FAMILY

309

Curiously enough, young blackbirds, like young thrushes,
are very distinctly spotted. There can be no doubt that
blackbirds »and thrushes are descended from the same stock,
and that their ancestors had spotted breasts. For some
reason, the blackbird has lost its family colours, although, as
is so often the case among animals, it is still compelled to
bear the marks of its ancestry during its infancy. Young
blackbirds also receive a musical education from their
parents, and may often be heard practising their song in
September or October.

The fieldfare, another near relative of the thrush, arrives
in this country about the beginning of October, and stays
with us for the winter, returning in spring to its nesting
places among the pines and firs of Norwaf. The general
colour of the bird is grey, with reddish-brown on the wings,
and its breast is speckled in the thrush-manner» Fieldfares
frequent fields in large parties, especially in the evenings,
but are readily alarmed. *

Other birds of the thrush family. — The redwing, wheat-
ear, whin chat, stone-chat, redstart, robin, nightingale, ^nd
hedge-sparrow are other members of the thrush family which
can here be only referred to. They have many points of
resemblance, one of the most interesting of which is that
the young birds are invariably spotted. The bill is usually
rather long, stout, and straight, the staple food being insects,
worms, etc., though fruit is also eaten, especially in winter.
The nests are typically cup-shaped, and the eggs greenish or
blue, with or without spots. The young birds are quite
helpless and almost naked when hatched, and can only
open their mouths to be fed by the parents. Even after
they have left the nest they need careful and continuous
teaching by the parents before they can be made to under-
stand that in future they will have to obtain their own food.
Birds of this family, on account of the variable character of

310 AN INTRODUCTION TO NATURE-STUDY

their food, are not so markedly migratory as many others,
although they generally move further southward in winter,
as the supply of insects becomes scarce — their place being
taken by birds which have spent the summer in more
northerly regions. * This habit is very obvious in the case of
the fieldfare and redwing, which visit us for the winter and
return to Norway and Sweden for the summer. The
nightingale, on the other hand, arrives here from the south
in April to build its nest and rear its young.

56. THE SWALLOW FAMILY, THE SKYLARK,
AND CROWS.

I. The Bwallo'fr. — (a) General appea,rance. — Notice, first of
all, the bird’s colouration, as this readily distinguishes the
swallow from the martins. The whole of the upper surface is steel-
blue ; the only white is on the ventral surface. A black band
stretches across the breast ; the throat and forehead are pink
Observe the long, deeply foiked tail, and the broad, short bill.

{8) Habits, — What are the earliest and l^est dates on which
you have seen swallows ? Do the birds seem to prefer the
neighbourhood of water? Have you ever seen them (i) perching
on trees, (ii) on the ground ? Why do swallows occasionally
alight on the ground? Do they seem comfortable on the
ground ? Observe the small and weak feet ; are these adapted
to a terrestrial life ? Do swallows feed on the ground ? What
do they eat? How are the insects caught? What is the
advantage of the very wide gape ? How would you describe
the flight of the swallow ?

{c) Voice, — Does the swallow sing? Describe its voice.
H ave you heard it when the bird was on the wing, or only when
it was at rest ? What kind of sound is uttered by the swallow
when it is alarmed or angry?

{(1) Nest. — In what situations have you found swallows’ nests ?
(Do not confuse the nest with that of the houses martin, which
lays white, unspotted eggs.) How soon after their arrival do the
birds begin to build ? What is the shape of the nest ? Of what

THE SWALLOW FAMILY

3 "

materials is it composed? How many eggs does it contain?
What is their colour?

{e) You hook for the newly-hgitched young about the last
week in June, and describe their appearance. How soon after
hatching do they leave the nest? Do they at once feed them-
selves, or are they fed by the parents ? fJeep the nest under
observation after the young birds have left it, and notice
whether the old birds rear another brood the same summer.

In September look for the annual congregation of swallows
which precedes their departure for Africa.

2. The house-martin. — Distinguish the house-martin from the
swallow by the patch of wdiite on the upper tail-coverts (Fig. 179),
and by the feathered toes. Make notes of the dates of arrival
and departure of the birds. Do house-martins occupy old nests
or build fresh ones? What are the position^ material, shape,
and size of the nest ? How does it differ from the swallow’s
nest ? Is the martin of sociable or solitary habits ? Watch the
birds building new nests or repairing old ones, and describe the
process. Examine and count the pure-white eggs. What arc
the newly-hatched young like? How l!iany broods have you
known one pair ot martins to rear in one season ? Have you
ever known martins to be turned out of their nests by sparrows ?
Watch for the autumn congregation.

3. The sand-martin. — Notice the srhall size of the bird, the
mouse-colour of the upper parts, and the black feathers of the
wings and tail. Note the dates of arrival and departure. Is
the bird often seen near houses ? Look for the nesting-holes in
cliffs, banks, etc. Examine the holes, and notice that they lead
into tunnels which slope slightly upwards. What is the use of
the slope? If possible examine the nest at the end of the
tunnel, and compare it and the eggs with tho^^o of the swallow
and house-martin. Observe the peculiar jerky flight. Does the
bird sing ? Describe its voice.

4. The skylark.— Does the skylark frequent woods or open
ground ? Describe the appearance, size, and colouration of the
bird, and try4;o see the long toes. Especially notice the long
claw of the hind-toe. Have you ever seen the bird perching on
trees or bushes ? Are the feet well adapted for perching ? Does

312 AN INTRODUCTION TO NATURE-STUDY

the skylark run or hop? In what month does it begin to
sing ? In March look for larks’ nests in hollows and ruts of fields.
What are the materials of tjie nest ? Describe the njimber and
appearance of the eggs. i Listen to the song, and try to say in
what respects it differs from that of other birds. Does the bird
sing only when flying, or also when on the ground ? Describe
the skylark’s flight, and study its method of soaring (p. 278).
Observe that the birds collect into flocks in autumn. Do they
leave the country for the winter ? How do they spend the
winter? Do they sing in winter? If possible examine the
beak ; for what kind of food do you think it best adapted ?

5. The rook. — Notice the size, shape, and colouration of the
bird. Do rooks live merely in pairs or in large communities ?
Do they build on the ground or in trees ? Are the trees high or
low ? What is tl^ largest number of rooks’ nests you have seen
in one tree ? Watch the birds repairing and building nests in
February and March. Of what are the nests composed? Have
you ever seen rooks stealing sticks from other rooks’ nests?
Are the birds quarrelsome? Where do they feed? Do they
hop or walk ? Do tftey keep together when feeding ? Do
all the birds of one rookery feed at the same time, or do some
remain in the trees ? Why ?

What is the shape of the beak ? How is this associated with
the food of the bird ? Do the farmers in your neighbourhood
consider rooks useful or the reverse ? Why ? What is the voice
of the rook like ? How does it vary to express warning, anger,
etc. Describe any observations \vhich lead you to suppose that
a colony of rooks has a code of laws. Describe the flight of the
rook ; what other birds fly in a somewhat similar manner ? In
spring, look beneath the trees for the broken shells of eggs which
may have fallen from the nests. What is their colour ? Describe
the appearance and habits of the young birds. Where do rooks
spend the winter? Have you ever seen them visiting and
inspecting their nests in winter ?

6. Other birds of the crow ftimily. — With the rook compare and
contrast the crow, raven, jackdaw, magpie, and jay.

The swallow family. — Swallows and martins are popular

THE SWALLOW FAMILY

313

with all lovers of birds, for many reasons. Their arrival is
welcomed as visible evidence of the approach of summer ;
their graceful and rapid flight delights the eye ; their
obvious liking for the neighbourhood of human dwellings
wins our sympathy ; and, lastly, they claim our gratitude
by their incalculable services in keeping down insect pests.

The swallow (Fig. 202) may readily be distinguished from
the martins by the absence of white from its upper parts,
which are glossy and of a steel-blue colour. I'he forehead,
chin, and throat are of a pink or chestnut colour ; the ventral
surface is white, with a black band crossing the neck. The
tail is long, and very deeply forked,
broad, and the gape stretches nearly
to the eyes — a great advantage to
a bird living on insects which are
caught flying. The feet are very
small and weak, but as the swallow
spends most of its time in the air,
and rarely alighta on the ground
except to collect materials for its
nest, it does not need very sturdy
hind-limbs, and the feet are chiefly
used for perching.

Swallows arrive in this country about the middle of April,
and about a month later proceed to build their nests in the
chimneys of houses and on the rafters of barns and out-
houses. The nest is basin- shaped and open at the top ; it
is chiefly composed of mud, which the birds collect on the
ground, place in position, and allow to dry. Short , ^straws
are used to bind the mud together, and the nest is lined
with soft grass and feathers. The hen lays from 4 to 7
eggs, which are a translucent white, with reddish-brown or
grey marking’s. The first brood of young is usually hatched
about the end of June, but a second or even a third brood

The bill is short and

Fio. 202. — The Swallow, (xj.)

314 AN INTRODUCTION TO NATURE-STUDY

may be raised before the parents depart for the south.
Gilbert White ^ gives the following charming account of the
training of young swallows : For a day or two tfiey are fed
on the chimney-top, and then are conducted to the dead,
leafless bough of, some tree, where, sitting in a row, they
are attended with great assiduity, and may then be called
perchers. In a day or two more they become flyers^ but are
still unable to take their own food ; therefore they play
about near the place where the dams are hawking for flies ;
and, when a mouthful is collected, at a certain signal given,
the dam and the nestling advance, rising towards each
other, and meeting at an angle ; the young one all the while
uttering such a little quick note of gratitude and com-
placency, that person must have paid very little regard
to the wonders of Nature that has not often remarked this
feat.” When the young bird has learnt to feed itself ‘^it at
once associates with the first brood of house- martins ; and
with them congregates, clustering on sunny roofs, towers,
and trees. , . . All the summer long is the swallow a most
instructive pattern of unwearied industry and affection ; for
from morning to night, while there is a family to be sup-
ported, she spends the whole day in skimming close to the
ground, and executing the most sudden turns and quick
evolutions. . . . When a fly is taken a smart snap from her bill
is heard, resembling the noise at the shutting of a watch case ;
but the motion of the mandibles is too quick for the eye.”

The swallow drinks whilst flying, sipping the water from
the surface of pools. Its song is a delicate and pleasing
warbl^ which is uttered both at rest and during flight. The
voice becomes a squeak when the bird is alarmed or angry.
Just before the autumn migration, swallows perch in crowds
on roofs, hedges, and the branches of trees. They leave for
Africa about the beginning of October.

^ The Natural History of Selborne,

THE SWALLOW FAMILY

31S

The house-martin may. be distinguished from the swallow
by the patch of white upon the upper tail-coverts, and by its
feathered t6es. Like the swallow, It arrives in this country
about the middle of April. The birds soon begin to repair
their old nests and to construct new ones njnder the eaves of
houses. The nest is largely composed of clay or mud, which
the birds collect from damp places in the road, etc., place in
position against the wall, and allowed to harden. The com-
pleted nest is somewhat bag-shaped, having only a small
hole at the top ; it is lined with soft grass. The eggs are
white, without spots. It is worthy of notice when a wild
bird lays white eggs, they are hidden from sight by the shape
or position of the nest, as in the case of the martins, or the
nest is built in an inaccessible place. Exposed eggs are
usually made more or less inconspicuous by being coloured
or spotted. House-sparrows (Fig. 208) have often been
known to expel the defenceless martins from their nests,
and to lay their own eggs therein. The eggs of the sparrow
may be recognised by their grey colour, and by the brown
blotches with which they are marked.

The structure of the martin, like that of the swallow, is
admirably adapted to a life in the air, and to a diet of flying
insects — the bird having powerful wings, small and weak
feet, and a soft and short but widely-opening beak. House-
martins leave us about the beginning of October.

The sand-martin is distinctly smaller than either the
swallow or house-martin, and it may be further distin-
guished from them by the “mouse-colour” of its upper
parts. It usually arrives in this country about a fortnight
in advance of its two relatives, and also departs before
them, leaving in August or September. These birds live in
colonies in tunnels which they excavate in banks or friable
cliffs (Fig. 203) — generally in the near vicinity of water.
The excavation may be three feet in length; it slopes

3i6 an introduction TO NATURE-STUDY

slightly upwards to the nest (which. is placed at the end of
the tunnel), in order that rain water may not collect in it.
The eggs are pure whit^, and five or six in min\ber. The

Fig. 203. — Sand Martins’ Nesting Holes.

birds are exclusively insectivorous; the) do not sing, but
utter a little twitter. The flight is very characteristic,

F.a. =o,.-Th. Skylax^ (xi.) ^

upon the ground. The
large toes lie flat on the earth, and the long claw of the
hind toe is plainly not very suitable for grasping the
twigs of trees in the act of perching. In fact, the sky-
lark only occasionally perches, on low bushes. Walking

THE SKYLARK

317

or running on the ground, it lives upon grubs, caterpillars,
flies, worms, etc.* and also upon seeds, which its strong beak
enables it to extract from the husks.. The body is brown, the
wings being streaked with black, and ibe dull-white throat and
breast being marked with brown spots— a polouration which
is a considerable protection. The nest is built in March, in
a hollow or rut on the ground ; it is lined with dry grass.

Fig. 205. — Skylark at Home.

The four or five eggs are greenish-grey, and spotted with
brown. Whilst the hen sits upon her eggs (Fig. 205) the
cock-bird either hunts for food or sings his delightful song
as he soars in the air. The wonderful powers of soaring of
this bird have already (p. 278) been referred to. When the
lark drops to the ground he alights at a little distance from
the nest, and then runs up to it through the grass. By this
device he avoids revealing the position of his mate and
young.

3i8 an introduction TO NATURE-STUDY

Skylarks rarely sing in the depth of winter ; in autumn
they form large flocks which patrol the fields until spring
in' search for food— r<^ndering incalculable cervices io
mankind by the destrtiction of insect-larvae. During the
coldest weather of winter the birds crouch under banks and
hedges.

The rook. — The rook (Fig. 206) — often called the crow —
is a rather large bird, measuring about 17 inches from
head to tail. Its plumage is black, but as it becomes adult
the feathers covering the face and nostrils are shed, leaving

the skin of these parts
bare. The bird has long and
pointed wings, and is a strong
flier. The bill is stout and
almost straight. Rooks are
no songsters, their harsh
‘‘ caw ” being destitute of
musical qualities. When
heard at . a distance, how-
ever, the cry “ becomes a
confused noise or chiding ;
or rather a pleasing murmur,
very engaging to the imagin-
ation, and not unlike the cry of a pack of hounds in
hollow, echoing woods, or the rushing of the wind in tall
trees, or the tumbling of the tide upon a pebbly shore.’’ ^
One of the most interesting features of rook-ways is
the habit of living in organised communities.- It is true
that a primitive form of social life is found among swallows,
martins, and (in winter) larks, reminding us of the gregarious
habits of the rabbit (Chapter XII.) among mammals ; but a

^ The Natural History of Selborne. *

** A delightful account is given in the story of “ Silverspot” (Thomp-
Son-Seton’s Wild Animals I Have Known).

.■.’Ar

Fig. 206. — The Rook, (x^ig.)

THE ROOK

.^19

rook-society is rather to be compared with the pack-life of
ihe wild dogs (p. 252), which depends for its integrity upon
the observance of certain rules of conduct by its members.
Naturalists have long known that such a code of laws is in
force in every rookery, but what these laws are we do not
fully understand. Here is a profitable and interesting field
of observation for the student. It has sometimes been

Fig. 207. — Rookb’ Nests in Trees.

observed that certain birds are prevented by the rest from
building until the nests already commenced are finished,
and cases have been known of birds being expelled from
the rookery, or even put to death, after a consultation or
“ trial,” presumably for some breach of law. On the other
hand, it must be admitted that rooks are generally arrant
thieves, not scrupling to rob their neighbours^ nests of
building-materials to save themselves trouble. They are
also very quarrelsome.

120 AN INTRODUCTION TO NATURE-STUDY

The nests are built on high trees (Fig. 207) ; they are
composed of sticks and turf, and are lined with moss and
soft grass. As each of “several adjacent trees often contains
a large number of nests, a sort of rook-town called a
“ rookery ” is formed. This is added to from year to year, as
the number of the birds increases. During the summer the
rookery forms the headquarters of the community, but about
August or September, before the leaves are shed, the birds
leave their nests, to spend the winter in thicker or evergreen
woods, often at some distance. At intervals during the
winter they revisit their spring nests. They come back to
the rookery in February or March, and at once set about
repairing old nests or building new ones. The male bird
begins to feecf the female even before the bluish-green eggs
are laid, and is a pattern of domestic virtue throughout the
period of incubation. P'or some time after hatching, the
young birds are fed by the parents. Rooks feed on the
ground in flocks, a tew birds remaining behind in the trees
as sentinels to give the alarm when danger threatens. The
food consists very largely of the larvae of injurious insects,
especially the grubs of the cockchafer beetle, and although
the birds undoubtedly eat corn and other young crops,
they do far more good than harm.

Other birds of the crow family. — The crow, raven, jack-
daw, magpie, and jay are so similar in many respects to the
rook and to each other that naturalists include them all in
one group, which they call the crow family.

The passerine order. — The families of the birds hitherto
considered in this chapter, with the flycatchers, wrens,
chats, tits, finches, linnets, starlings, etc., are further
grouped together to form what is called an order. The
order which consists of these families derives its name
passerine from the sparrow^ (Fig. 208), perhaps the com-
^ Latin, passer , a sparrow.

SWIFT AND THE CUCKOO

321

monest of the birds included in it. It is probably in this
order that bird structure attains its most perfect development.
Again, the^ birds of the crow family are generally considered
to stand at the head of the order > if this view is correct,
rooks must be regarded as occu-
pying, among birds, a position
which roughly corresponds to
man's place in the class of
mammals.

Passerine birds are nearly all
singers, and their toes are gener-
ally adapted for perching. They
feed upon insects, seeds (especi-
ally the seeds of grasses), and
soft fruit. Their beaks vary in
form according to the nature of the food upon which
they most depend, as is well shown by the soft, widely
opening bills of the swallows, the string but slender beaks
of the thrushes, larks, and crows, and the short, hard
beaks of such seed-eaters as the canary, sparrow, and other
finches. Birds which are exclusively, or almost exclusively,
insectivorous are compelled to migrate to warmer countries
to obtain food during the winter. The eggs of passerine
birds are usually coloured or spotted, and the young birds
are hatched in a helpless and almost naked condition,
being carefully tended and fed by both parents until they
are able to fend for themselves. A few familiar birds of
other orders will now be briefly considered.

57. THE SWIFT AND THE CUCKOO,

I. The swift.— Distinguish the swift from the swallow by its
larger size, its sooty black colour (except for the dull white of the
throat), and its long, bowed wings. In what respect does the
swift resemble the swallow ? Watch for the appearance of
N.S. X

Fig. ao8. — Sparrows, (x i-)

322 AN INTRODUCTION TO NATURE-STUDY

swifts about the end of April. Do the birds arrive singly, in
pairs, or in flocks? Notice the rapid turns and twists of the
flying bird. Does it as a rule fly near the ground, or at some-
what great heights ? Have you ever noticed the bird perching,
or settling on the ground ? Have you seen it clinging to walls
with its feet ? Were these the walls of houses or barns, or of
high towers ? What actions would lead you to suppose that the
nests are built in high towers ? Are more swifts to be seen in
the evening, or during the day ? Can you explain this ? Watch
during the first half of August, and make a note of the day
on which swifts were last seen.

*2. The cuckoo. — What is the earliest date on which you have
heard the cuckoo ? Imitate the cry by putting your hollowed
hands together and blowing between the thumbs. With practice
you will be able to deceive the bird into thinking that another
cuckoo is presenV, and it will approach near enough to be seen
distinctly. Estimate the size of the bird, and write down a
careful description of its form, colouration, and method of flight-
Try to see that two of its toes point forwards and two back
wards. Have you ever seen cuckoos mobbed by small birds ?

Carefully examine as many nests of small birds as possible,
and try to find one containing an egg sliglitly larger than the
rest and perhaps differently coloured. This will probably be a
cuckoo’s egg. Visit the nest at frequent intervals, both before
and after the hatching of the eggs, and write descriptions of the
eggs, the appearance and size of the young birds, what becomes
of each, and the behaviour of the old birds. What is the latest
date on which you have heard the cuckoo ?

The swift. — Though the swift bears a strong general
resemblance to the swallow, the two birds are not at all
closely related, but belong to different orders The swallow,
like all other passerine birds (p. 320), has 12 tail-feathers,
and its first toe is separately movable and directed back-
wards. The swift, on the other hand, has only 10 tail-quills,
and all its toes point forwards. There are, however, more
obvious differences, which readily enable one bird to be dis*

THE SWIFT

323

tinguished from the other, even at a distance. The swift is,
with the exception of a dull-white patch on the throat, of a
sooty black? hue over all the body, and in flight its long and
powerful wings take the form of i. bent bow (Fig. 209).
The swallow flies in bold, sweeping curves, while the more
rapid swift turns sharply in the air, in pursuit of the flying
insects upon which it feeds, in a manner suggestive of the
flight of a bat. While, again, the swallow flies much near
the ground, the swift is usually
seen at greater heights. The
harsh scream of the swift is,
moreover, in marked contrast
with the swallow’s pleasing
song.

Swifts do not willingly alight
on the ground, even to collect
materials for their nests, nor do
they perch on trees or roofs,
the arrangement of their toes
being quite unsuitable for either
action, and the length of the
wings being such that, even
with toes of the normal type,
walking would be almost impossible. The nest, a somewhat
rude structure of grass and feathers, is generally built in
high towers or other tall buildings. The eggs are two in
number ; they are more conical in shape than those of the
swallow, and, as the position of the nest renders them
independent of protective colouration, are white. The hen-
bird sits on them during the day, but generally leaves the
nest and flies abroad in the evening to hunt for insects.
Only one brood is reared, and the birds take their departure
early in August, to spend the winter in South Africa or
Madagascar.

Fig. 209. — The Swift. (X^.)

324 AN INTRODUCTION TO NATURE-STUDY

The cuckdo. — The cuckoo is placed by; naturalists, not
among the passerine birds, but in the order to which the
swift belongs. The reasons for this cannot hi fully con-
sidered here, but it may be mentioned that the cuckoo
has only lo taU-feathers, and that it differs from all
passerine birds in having its fourth toe, as well as the first,
directed backwards, the second and third pointing forwards
(Fig. 2io).

The cuckoo has a total length of about 14 inches. The
upper surfiice of the body, and the throat, are grey ; the rest
of the lower surface is white,
crossed with black bars. The
wings are large and powerful, and
the thighs are covered with long
feathers. In general appearance,
as well as in manner of flight,
the cuckoo bears a great resem-
blance to a hawk, which may
perhaps be the ‘ reason why small
birds so often join forces and attack
it. A keen-eyed observer will,
Fig. 210.— The Cuckoo, (xj.,) however, at once distinguish the
birds by the head and the bill,
both of which are markedly longer in the cuckoo than
in the hawk. Cuckoos arrive here in April, the males
usually appearing first. The well-known call, to which the
bird owes its name, is uttered by the male only ; the voice of
the female is quite different, and is often compared to the
sound of bubbling water. The cuckoo feeds entirely upon
insects ; it is believed to be the only bird which eats the
hairy caterpillar of the tiger-moth (p. 369).

Of all bird-habits, probably none has excited more interest
than the manner of life of the young cuckoo. Its parents
build no nest, but depend entirely upon other birds for

THE CUCKOO

325

rearing their ofK^pring. The female cuckoo lays her egg
upon the ground and then carries it in her bill to a nest
which confeins similarly coloured • eggs, if such a nest is
to be found. If not, another convenient nest is selected.
It is said that the male sometimes winders assistance
by distracting the attention of the rightful owners in
the meantime. In most cases the owners of the nest,
apparently unaware of - the trick, sit upon the strange egg

Fig. 211. — Cuckoo’s Egg in Greenfinch's Nest (Cuckoo’s Egg on the right).

with the rest, and in due course the young birds are hatched.
The young cuckoo, whilst still blind and naked, wriggles
itself under its foster brothers and hoists them over the edge
of the nest. Far from resenting the crime, the duped
parents now devote their energies to feeding the murderer,
and continue their attentions until after it is fully fledged
(about a fortnight after hatching) and perhaps several times
their combined size.

The small size of the cuckoo’s egg — about one-fourth of
what might be expected from so large a bird— and its

326 AN INTRODUCTION TO NATURE-STUDY

general similarity in colour to their own eggs, both aid in
deceiving the victimised birds in the first instance, and
the disproportionate size* of their supposed offspling shortly
after hatching apparently does not arouse their suspicions.
It is believed that any particular female cuckoo lays only
eggs of one type and deposits them, as far as possible, in
nests of the mimicked species — the species, probably, by
which she herself was reared. During the summer, there-
fore, she visits one such nest after another, until she has
disposed of all her eggs. Further, it is supposed that her
offspring inherit her tendency to lay eggs of the particular
colour, and therefore to prey in their turn upon the species
of their foster-parents. In this country, the meadow
pipit, pied wagtail, robing and reed-warbler are perhaps the
most usual victims of the cuckoo's parasitism, hut the
nests of other species (Fig. 211) are not uncommonly
selected.

The old cuckoos depart about the end of July, apparently
leaving the young ones to find their way kouth alone.

58. THE DUCK.

I. Tame ducks. — Closely observe ducks, both on land and when
they are swimming. Where is the heaviest part of the body ?
Are the legs attached in front of, directly below, or behind the
centre of gravity? Is the position of the legs an advantage or
a disadvantage (i) in walking, (ii) in swimming ? How does the
foot differ from the feet of the birds previously mentioned ?
Between which toes is the web stretched? How are the toes
held when the bird lifts its foot in walking? Does it walk
gracefully ? How does it swim ? Are the legs moved together
or alternately in swimming ? Notice how the web folds up
when the foot is moved forwards, and spreads out for the
back-stroke. What does the duck eat ? How is the food
obtained ? Why are a duck’s feathers so little wetted by the

THE DUCK

327

water? Watch, and describe exactly, how the bird preens its
feathers.

How can' you distinguish the malt (drake) from the female
duck, (i) by appearance, (ii) by J:he voice ? Do the colours of
the drake’s plumage differ at different periods of the year?
What relation have the changes of plumage to the moul ting-
season? What differences can you observe in the methods
of moulting of ducks and fowls? Is there any time of the year
when (i) ducks, (ii) fowls are unable to fly ? Why ? When and
where do ducks lay their eggs? Describe the appearance of
the eggs. Are young ducks helpless or precocious (p. 296),
naked or clothed, at hatching ? Can they feed themselves ?
Can they swim ?

Examine a dead duck. Notice the thick covering of down-
feathers next the skin. What is its use ? Examine and draw a
foot, and see how the web folds between the toes. Observe the
soft, sensitive skin on the outside of the beak ; what do you
suppose is its use? Notice the shape of the beak. Open it to
see the horny plates fringing its inner edge, and notice how
these, with other plates on the thick, fleshy tongue, form a
strainer. •

The duck, — The birds of the duck order — which includes
also the geese and swans — differ in many important respects
from all our previous types, and it is interesting to observe
how perfectly these differences are adapted to the manner
of life. On land, the ungainly waddle, which is entailed by
the insertion of the hind limbs so far back on the body
(Fig. 212), shows that the duck is not in an entirely con-
genial element ; in the water the bird is a model of graceful
movement, perfectly balanced, progressing smoothly by
alternate strokes of its webbed feet, and altering its course
to any desired direction with the utmost ease. The duck
feeds largely* upon the small animals which abound in the
water of ponds, and in the mud of the sides, and the beak
is beautifully fitted for the duties it has to perform. It is

328 AN INTRODUCTION TO NATURE-STUDY

covered on the outside by a soft and highly sensitive skin,
which enables the bird to detect with certainty the presence
of its prey in the mild,; the inner edge of the beak is pro-
vided with horny plates which, with similar plates situated
on the edge of the’ thick, fleshy tongue, form a very efficient
strainer, by means of which the useless water and thin mud
can be forced out at the sides of the mouth and separated

Fig. 212.— Ducks.

from the worms, etc., which were taken into the mouth at
the same time. A thick coat of down-feathers, which lies
next the skin and contains a great deal of entangled air,
forms a non-conducting layer which prevents the undue
escape of the heat of the body, and saves the bird from
becoming chilled when in the water. Ducks are, moreover,
careful to keep their feathers well oiled, and may often be
seen preening themselves — applying the bill alternately to
the oil-gland on the tail and to the feathers. The complete-
ness with which water flows off a duck’s back is proverbial.

TWO COMMON HAWKS

329

During the greater part of the year the brilliant plumage
of the drake forms a striking contrast to the sober brown
and grey feathers of the female. A*r^other point of difference
is that in the male the four middle tail-feathers are curled
upwards. From July to October, howevt?r, before the moult
takes place, the two sexes are very similar in appearance.
Birds of the duck order moult in a somewhat different
manner from most other birds, in that all the quill-feathers
are shed at once, instead of in pairs. Until the liew feathers
develop, flight is of course out of the question, and the birds
remain as secluded as possible in the meantime.

The eggs are white and greasy-looking ; they are laid in a
rough, open-topped nest, lined with down, which is placed
on the ground. The wild duck t:overs u^ the eggs when
she leaves the nest. The young are active immediately
after batching. It has been noticed that the eggs of
precocious birds are generally larger, in proportion to the
size of the parent, than those of birds which are naked and
helpless at hatching — the larger store of egg-food allowing a
more complete development of the young bird in the shell.
Further, the nests of precocious birds are, as a rule, less
elaborately constructed.

59. TWO COMMON HAWKS.

1. The sparrow-hawlL — Watch for sparrow-hawks near farms.
Notice the general resemblance of the bird to the cuckoo, but
distinguish them by the short head and beak of^the hawk.
Observe the bluish-grey colouration of the upper parts.
Describe the flight of the hawk and, if possible, its method
of catching its prey.

2 . The kestrel or windhover. — Distinguish the kestrel from the
sparrow-ha\\1c (i) by the reddish colour of its upper parts, and (ii)
by its habit of hovering in mid-air. Have you ever known
the kestrel to prey upon small birds ? Upon what does it feed?

330 AN INTRODUCTION TO NATURE-STUDY

The sparrow hawk and kestrel— These mo birds are the
only British hawks which the average nature-student is likely
to see during a country walk ; and as one of them^ is given to
preying on young game-birds, chickens, etc., while the other
as generally confinvjs itself to animals which are universally
regarded as vermin, it is important to be able to distinguish
them at sight.

The sparrow-hawic (Fig. 213) attains a length of 13 inches ;
the female is slightly larger than the male. The upper parts

Fig. 213. — The Nest of the Sparrow Hawk.

of the body are bluish-grey in colour ; the lower parts are
buffish white, and crossed with brown bars. The head is
short and round ; the bill is hooked and sharp, as in birds of
prey generally, and the toes are armed with sharp claws.
The bird' is often to be seen near farms, lurking behind
hedges and waiting for an opportunity of dashing upon
chickens or other small birds and carrying them off.

The kestrel, which in size and shape much resembles the
sparrow-hawk, is really a species of falcon (Fig., 17 9). It is
unrivalled among common British birds in its power of
remaining poised in one position in mid-air by that rapid

TWO COMMON HAWKS

331

motion of the v^ings which is called hovering, a power which
has earned for it the name of ‘‘ windhover/’ The kestrel,
though in Veality one of the farm^Jr’s best friends, from its
wholesale destruction of field-mice, voles, and many in-
jurious insects, is often ignorantly Cjonfused with the
sparrow-hawk.. The reddish hue of the plumage of the
kestrel’s upper parts, together with the hovering habit, ought
to render such a mistake impossible to observant eyes, and
to secure the bird from a persecution which may reasonably
be directed against the sparrow-hawk.

EXERCISES ON CHAPTER XVII.

1. Extend the foregoing methods of s*udy to th^ following passerine
birds : — Starling, finches, wagtails, pipits, nuthatch, tits, warblers,
wrens, and flycatchers, and make notes of the observations.

2. Try to discover reasons for grouping (a) woodpeckers, nightjars,
and kingfishers with swifts and cuckoos ; pheasants and giouse with
fowls.

3. Compare geese and swans with ducks, and make notes of as many
points of resemblance and difference as possible.

4. Compare and contrast owls with hawks.

5. Arrange the above birds in lists according to {d) food, and the
characters of the beak ; {b) characters of feet and arrangement of toes ;
(c) nests (open-topped, covered, built in holes or tunnels) ; (d) colour
and number of eggs ; {e) condition of young at lime of hatching.

6. How many birds do you know which {a) spend nnly the summer,
{b) spend only the winter, (r) stay all the year, in this country?
State, in each instance, upon what food the bird most depends.

CHAPTER XVIIL

FROGS AND TADPOLES.

60 THE LIFE OP THE FROG.

1. Maimer of life. — Where have you found frogs ? Are they
commonest in dr^or in damp situations ? At what time of the
yealr have you seen them actually in water? How do frogs
move about ? Do they walk or hop ? Chase a frog, and notice
that its hops become shorter as it is pursued. Upon what does
the frog feed ? Have ycau ever seen frogs abroad in the depth of
winter ? Are insects common in winter ? Hpw do you suppose
frogs spend the winter? What are the principal enemies of frogs?

2. External characters, — Catch a frog ; is its body dry or
moist ? Does it feel cold or warm ? How does it behave when
caught ? Does it soon become tame if well treated. Put a frog
under an inverted pickle-bottle and observe it carefully. What
is its size ? What was the size of the smallest frog you have
seen ? At what time of the year can the smallest frogs be seen ?
What is the colour of the frog ? Put one frog with dark-
coloured leaves and soil, and another with light-coloured leaves,
and try to find out if the skin of the first becomes lighter and
that of the second darker in colour. Is it an advantage to the
frog to be able to change slightly in colour? Why? What is
the position of the frog when at rest? Notice the shortness of
the body, the hump on the back, the relative lengths of the
limbs, the 4 unwebbed fingers, the 5 webbed toj^s, and the
absence of a tail. What is the advantage of the long hind-
limbs? Mention other leaping animals whose hind-limbs are

THE LIFE OF THE FROG 333

longer than the fore-limbs. Is a short-bodied animal (z.^. one
with its four limbs pretty close together) less likely to be injured
by the falls after a leap, than a long-bodied animal? Why?
Put the frog into water, and watch it s?wim. What is the use of
the webs between the toes? Examine the head. Notice the
very wide stretch of the mouth, the small openings of thp
nostrils, the large prominent eyes, and the ear-drum — a dark-
coloured disc on each side, a little below and behind the eye.

3. Breathing. — Watch the up-and-down movements of the
floor of the mouth, by which the animal pum[)S air, through its
nostrils, in and out of its mouth-cavity.

4. Method of feeding. — Put live insects, small worms, etc.,

under the upturned bottle enclosing the frog, and watch the
animal’s method of feeding. Try to see how it uses its tongue.
What is the advantage of the wide gape of ^le mouth ? Can
you get the frog to accept dead inseJts ? ^

5. The inside of the mouth. — To kill a frog painlessly, soak
about a teaspoonful of chloroform on cotton wool, and put
it with the frog under a bottle or tumbler. After 15 or 20
minutes the frog will be quite dead. ®

(d ). — Open the Jews widely, and examine the inside of the
mouth. Notice how the rounded eye^balls project into the
mouth-cavity when they are pressed from the outside. Pass
your finger-end round the margins of the jaws, and feel the
row of fine teeth borne by the upper jaw ; the lower jaw is
destitute of teeth. Feel also, in the roof of the mouth,
two small patches of teeth (Fb., Fig. 216); these are
carried by small bones called the vomers, and are therefore
called the vojiicrine teeth. Just to the outside of the vomerine
teeth and in front of the eyeball, notice on each side the internal
opening of the nostril {Ch., Fig. 216) ; pass into one nostril
a stiff bristle, and observe that it emerges at the external nostril.
Pull forward the tongue (T, Fig. 216) and observe that it is
attached at its front end ; feel how sticky the tongue is. Behind
the eyes, and at the angles of the jaws, notice the openings of
the Eustachian tubes (.S', Fig. 216) ; push a stiff bristle into one
and observe, from the outside, that the end of the bristle presses
the inner surface of the ear-drum.

334 AN INTRODUCTION TO NATURE-STUDY

(^). —If the roof of the mouth has dried, moisten it with water,
and place a very small cork-shaving or a tiny snip of paper on it,
far back between the eyeballs. Notice that the shading travels
slowly down the throat. This experiment ought to be made

soon after the frog has been killed.

6. The bones. — Feel, through the body-wall, the various parts
of the skeleton, making out the skull, backbone, limb-bones and
their manner of attachment, and breast-bone (protecting the
heart). Observe the absence of ribs.

7. The skin. — Examine the skin of the dead frog, and notice
that it is damp or even somewhat slimy, and that it differs from
the skin of a mammal or bird in being naked^ bearing neither
hairs, feathers, nor scales. Pinch up the skin, and notice how
very loosely it is attached to the underlying body-wall. Snip
through the thin ^skin, turn it back from the body- wall, and see
the network of blod d-vesscU upon its inner surface.

The habits of the frog. — The common grass frog (Fig.
214) is to be found in abundance, from early spring to
October, in ditches, ^marshy land, and other damp places.
As winter approaches, frogs generally bury themselves in the
mud at the bottom of ponds, etc., and remain there in a
state of torpor until the spring, when they emerge and the
females lay their eggs. Frogs are said to be “cold-blooded
because their temperature never varies much from that of
their surroundings. Birds and mammals, on the other
hand, maintain an almost constant temperature, — a healthy
man’s blood, for example, being just as warm in the depth
of winter as it is on a hot summer day. So long as they
are not actually frozen hard, therefore, frogs can endure the
winter cold without much inconvenience. Although the
frog is essentially a land animal, it is quite at home in the
water, and swims gracefully and easily by the help of the
webs which connect the long toes of its hind feet. On land,
it progresses by long leaps, its limbs and body being well
adapted to this habit. As is usual in leaping animals, the

THE LIFE OF THE FROG

335

hind legs and feet are markedly longer than the fore limbs;
and the shortness of the body enables the two pairs of limbs
to be brought together to break the .shock of the fall.

Food. — The frog’s method of catching its prey is very
interesting, and is graphically described by Dr. Hans
Gadow^ as follows : — “The food, which consists chiefly of

Fig. 214. -T)ie Ft or. ( xt .)

insects, snails, and worms, must be moving to excite
intereist ; then the frog, whose favourite position is half
squatting, half supported by the arms, erects itself and,
facing the insect, turns round upon its haunches, adjusts its
position anew by a shifting of the legs, and betrays its
mental agitation by a few rapid movements of the throat.
All this time the prey is watched intently until it moves ;

^ The Cambridge Natural History^ Vol. VIII. (Macmillan.)

336 AN INTRCff)UCTION TO NATURE-STUDY

then there follows a jump, a flap of the tongue, and the
insect is seen no more.” This flap of thb tongue is well
illustrated in Fig. 215. , The frog^s tongue is free behind,

but is attached, by its anterior
end, close to the middle of
the lower jaw,— an arrange-
ment which enables it to be
flicked out to its full length.
Further, it is covered by a
glutinous secretion, which
sticks tenaciously to the prey.

The frog is fortunate also in
the extremely wide gape of
its mouth, which stretches,
almost literally, from ear to
ear. Once in the mouth, the
captive is prevented from
escaping by the teeth. Of
these there are two sets j a
row of fine teeth is present
along the greater part of, the
margin of the upper jaw, and,
in addition, two small patches
of teeth — the vomerine teeth
{Vo,, Fig. 216) — occur on the
roof of the mouth. Fairly
large insccts are promptly
gulped down into the stopach ;
those which, owing to their minute size, escape being
swallowed in the ordinary manner, are slowly but surely
forced down the throat by the incessant lashing of thou-
sands of tiny threads — too small to be seen except by
high powers of the microscope — which are carried by the
skin of the roof of the mouth. The action of these invisible

THE LIFE OF THE FROG

^37

threads may easily be seen if a frog’s mouth be opened
widely and a small cork-shaving be placed near the top of
the throat (Expt. eo, 5, d). I'he 'shaving steadily travels
backwards and is soon lost to sight. '

It should be clearly understood that f^jogs and toads are
of incalculable value in keeping down insect pests, and
deserve systematic protection for this if for no other reason.

How a frog breathes. — When a
resting frog is watched, the floor of
the mouth is seen to be raised and
lowered alternately. It is a common
belief among children that these
movements are a sign that the
animal is getting ready to spjj;.”

Frogs do not spit, however, and the
action is simply a part of the breath-
ing process, which is performed in
the following manner. The mouth
being closed, the nostrils are opened,
and, by alternate up and down move-
ments of the floor of the mouth, the
air present in the mouth-cavity is completely replaced by
fresh air. The nostrils are then closed, and the slit like
glottis {gL, Fig. 163) which leads to the lungs (/. I fig.,
r. lug.) is opened. The foul air is forced out of the lungs
and mixed with the pure air in the mouth-cavity, d hen,
immediately, the floor of the mouth is raised- pumping
the mixed air into the lungs -and the glottis is closed.
In the lungs an exchange takes place between the oxygen
of the refreshed air, and the surplus carbon dioxide in
the blood which is circulating in the capillaries (p. 242)
of the walls ^ of the lungs. In the meantime the nostrils
have again been opened, and the first stages ol the process
are already being repeated.

N.S. Y

■ I - ■ ■ tul- • .V,
< ■ i::i .■ !■ . .!.l nral

s.'v^ ; 1 , tongue ; /' "t?, vc ner-
ine teeth. (X i.)

338 AN INTRODUCTION TO NATURE-STUDV

A considerable part of a frog's breathing is carried on, in
these first stages, througli the thin membrane forming the roof

of the mouth-cavity. I'hisds richly supplied with blood capil-
laries, and is therefore admirably adapted for the exchange of

^ases which constitutes respiration. Moreover, the sMn
covering the general surface of the body has also a very abun-
dant blood-supply, and forms yet a third respiratory organ ; so
that it is practically impossible to drown a frog in ordinary
water — in water, that is, which contains dissolved air. This
power of breathing through the skin is of great importance to
a frog during the winter sleep at the bottom of a pond.

The frog's skin. — The frog’s skin is kept moist by a slimy
fluid which is continually being discharged from small
glands in its siffc^'Stance. < The moisture not only facilitates
skin-breathing as a>scribed above, but its evaporation keeps
the body cool even in hot weather— a matter of vital
importance to an animal to which a temperature of 40° C.
or so is fatal. A third most interesting property of the frog’s
skin is its power of changing somewhat in colour to match
the colour of its surroundings. The change depends upon
an alteration in form and size of certain small brown spAks
imbedded in the thickness of the skin. When the animal
finds itself in dark -coloured surroundings these specks en-
large, and the skin as a whole takes on a darker hue, On a
light background the reverse change takes place.

A case of evolution. — The advantage which accrues to a
frog from being thus rendered less conspicuous to enemies
and prey alike is obvious, and there is no difigculty in
picturing to ourselves the probable manner in which the
advantage was developed. Widely different races of animals
have colour-specks in the skin, and we may assume that
frogs and their ancestors have possessed such spots for
couptless generations. Now suppose that, ages ago, a frog
happened to be^born with the power of altering very slightly

THE LIFE OF THE FROG * 339

the size of his ^colour-specks. If this power rendered him
less conspicuous, in however slight a degree, than his
neighbour frogs he would, other things being equal, be more
likely than they to escape from, enemies, grow to maturity,
and in due course have sons and dpghters. All his
offspring, and they might number thousands, would tend to
inherit, to varying extents, the power of changing colour. In
some — perhaps in most— the power would be practically
absent; in*dthers it might be equal to that of the parent;
while in a few instances it would probably be greater. In any
case, those frogs of the second generation which had the
greatest power of changing their
colour would be the most likely to
survive the keen struggle for exist-
ence and therefore to leave offspring.

The survival of the “fittest” frogs
of each generation, and the trans-
mission to the next generation,
in ever-increasing* intensity, of their
favouring accomplishment, w^ould
naturally result at last in the pro-
duction of a race of animals in which, as in the frogs
of to-day, the power of changing colour is universal.

The laying of the eggs. — About the end of March the
frogs resort in ^great numbers to shallow ponds and ditches,
pair with much croaking, and the females lay their eggs or
“spawn.” Both sexes croak, and the male of the edible
frog, though not of the common grass frog, is able to make
more noise in virtue of a pair of vocal sacs (Fig. 217),
which he can inflate with air from the mouth (Fig. 216),
and which act as resonators. After spawning, the frogs
leave the water, abandoning the eggs to their fate, and
resume their ordinary terrestrial life, until approaching
winter prompts them to hide in the mud and go to sleep.

Fig. 217. — Head of Male
Kdible Fro^, seen from the left
side, showing inflated vocal
sacs. (X I.)

AN INTRODUCTION TO NATURE-STUDY

61. THE DEVELOPMENT OP THE FROO.

1. A simple aquarium. A simple aquarium, in which the
development of the frog from the egg may be watched, is easily
made. Obtain a f&,irly large basin, and cover the bottom with
sand, mud, and stones from a pond. Arrange these so that the
bottom shall shelve from the surface of the water at one side to a
depth of 3" or 4" at the other. Put in some stones covered with
green slime, which will almost certainly be found in the pond,
plant a few water weeds, and allow the water to clear.

2. Frog spawn. — Having prepared the aquarium, obtain, to-

wards the end of March (or earlier in a mild spring) a handful
of frog spawn from a pond or ditch. It forms a mass of jelly in
which the true ^gs — small balls about in diameter — are
imbedded. Put ti^^s in tht aquarium and examine it carefully
every day, making'- the observations described below. If
possible, obtain a pair of spawning frogs, and place them in a
bucket with a little water, so that the earliest stages also may
be studied. *

3. The eggs before hatching.— Observe the globe of jelly which
surrounds each egg. Try to pick it up between your finger and
thumb. Do you think it is of any use in protecting the eggs
from being eaten by fishes, birds, etc. ? Remove the jelly as
completely as possible from one egg, put the egg in a watch-
glass with a little water, and examine it carefully with a strong
lens. To which of the stages shown in Fig. 218 does it cor-
respond? If possible, treat a newly-laid egg in the same
manner and examine it every hour or so through the day.
Make notes of the time elapsing between the various stages
shown in Fig. 218.

4. Hatching. — Notice that the developing eggs change from
the spherical to the ovoid form. What is the shape when the
embryo begins to move? Notice the appearance of a neck
and a tail. At this stage the embryo makes its way out of
the jelly, or hatches. The ielly may now be thrpwn away, as
it is of no further use. How does the embryo behave immedi-
ately after hatching? Put one in a watch-glass and with a

THE DEVELOPMENT OF THE FROG 341

lens try to see the sucker by which it attaches itself to water-
weeds, etc.

5. Tadpol^ood. — Examine the tadpples at frequent intervals
by the help of a lens, and write careful> accounts of the changes
which take place in them. Notice particularly the fine threads—
the external -which grow out from thd sides of the neck.
How many are there? After a time they shrivel up and are
replaced by other gills which cannot be seen. Write a descrip-
tion of a tadpole at the time when it begins to feed. How
large is it?

Count the tadpoles in the aquarium at intervals of a few days,
carefully I'emoving all dead ones. Supply fresh green slime
from the pond from time to time. Have you any reason to
suppose that tadpoles are cannibals ?

How soon do the tadpoles come to the surface to breathe air?
Describe the appearance of one W*hen it ^gins to do this ?
Has it any legs ? How many can you see ?/ In what order do
the legs grow out ?

Notice now the dwindling of the tail. (It does not drop off, as
is so often stated.) The tadpole has l>>ecome a frog. What
percentage of the osiginal eggs have developed into frogs ?

The early development of the frog’s egg.— A frog’s egg is
a little spherical mass about one-tenth of an inch in dia-
meter. When laid, it is covered by a thin gelatinous layer
which soon swells up in the water to form a trans{)arent
globe of about half-an-inch diameter, in the centre of which
the true egg can be seen. This jelly is extremely slij)pery
and difificult to grasp, and is consequently an efficient
protection against the attacks of birds, fishes, insect-
larvae, etc., and even of parasitic fungi and other small
organisms. The jelly also acts as a float. At the time of
laying, each egg consists of a black and a white portion. In
the lower, or white, part there is a store of food, on which
the little embryo subsists until it acquires a mouth and begins
to fend for itself. The development begins in the upper, or

342 AN INTRODUCTION TO NATURE-STUDY

black, part of the egg, and may easily be , watched with a
lens. And to b® appreciated properly, the changes should

bife watched, and not ifjerely read about. The student
should get, if possible, some freshly-laid frog’s eggs, and

Fig. 2i8. — The carry development of the Frog, mi^ small black cells ;
large white yolk-cells ; ect^ black cells overspreading yolk-cells ;
yk.pl^ yolk-plug ; md.g 7 -, groove of commencing nervous system ; md.f^
right margin of groove ; br.cl, depressions marking position of future
gill -slits ; stdm, pit which will become mouth ; t, tail ; br,i^ br,2^ ex-
ternal gills; <r, eye; a A, sucker. (X5.)

remove the gelatinous investment from one or two. It will
require care to do this without injuring the eggs. They
should now be put, with a little fresh water, into a watch-
glass, and carefully examined at intervals of half an-hour or
so. Soon a little pit makes its appearance in the middle of
the black half, and gradually extends until it becomes a
groove, which little by little reaches quite round the egg

THE DEVELOPMENT OF THE FROG

343

(Fig. 218, A). ^In the meantime another groove begins to
form at right angles to the first, and, in its,turn, grows down

round the; egg (B). If we compare the whole egg to the
earth, and the middle of the black half to the North Pole,
these two grooves may be said to be along meridians at right

angles to each other. The third groove ( C) may be considered
as along a parallel of latitude, but it is somewhat to the north
of the Equator. These first three grooves deepen until the
whole egg is cut up into eight separate pieces. The sight of
the apparently lifeless speck dividing itself up in this regular
and orderly manner, ‘‘while you wait,” is an intellectual
treat which should not be missed. The cleavage of the egg
goes on rapidly, but in a less regular manner now, until the
whole is cut up into a hollow sph(ire of se^^ments (B), black
and small (mi) in the northern hemis/nere, whitish and
larger (mg) in the south.

It is worth while to pause here to consider liow these early
changes are assisted by the peculiar condition of the egg at
the time of laying* The southern hemisphere of the egg is
laden with a store of food. The food is dead, and acts as
a mechanical hindrance to the activity of the living matter.
In the northern half of the egg but little food is present
to impede its activity, and it is plainly important that this
half shall receive as much warmth as possible from the
uncertain sunshine of early spring. Two circumstances
ensure this. In the first place, the food-laden region is the
heaviest part of the egg, so that the latter — buoyed up as
it is by the jelly — tends to float with its most “ alive ” fiart
upwards. Secondly, this upper ^part is coloured blac'k,-^
a great advantage, since black objects absorb heat readily.
Both these pfeculiarities therefore favour the more rapid
development of the “ northern ” hemisphere. Hence the
third cleft is to the north of the egg’s equator, instead
of being half-way between the upper and lower poles,

344 an introduction to NATURE-STUDY

and hence, too, at the close of segmentatipn the northern

segments are smaller and more numerous than the southern.
In the case of the hen’s ‘hgg (Chapter XVI.), the amount of
stored food contained in the egg (the yolk) is so enormous
that segmentation ois confined entirely to a small patch on

the upper surface. Another result of the relatively small
amount of stored food in the frog’s egg is that the tadpole
is compelled to turn out and earn its own living at a stage
when the chick's inherited fortune is still considerable.

The tadpole. — The spherical mass soon becomes ovoid,
and is divided into head and trunk by a neck-constriction
{/). An occasional wriggle shows that the creature is alive.
Shortly afterwards a tail grows out from the hinder end of the
trunk, giving th?^animal something of the appearance of a
fish (Z). In this Y'jage the tadpole makes its way out of the
jelly, and thus hatches, about a fortnight after the laying of the
eggs. The little creature is quite helpless ; it has no mouth
(the egg food is not yet exhausted, however), and its attempts
at swimming are still feeble and uncertain. In this defence-
less condition (Fig. 219, i) it will be seen to attach itself to the
water weed of the aquarium by means of a sucker (Fig. 218,
Z, sk) on the underside of its head. It is in a very favour-
able position for examination, and by help of a lens, two —
soon there are three — pairs of fine, threadlike outgrowths
can be distinguished on the sides of the neck (Fig. 219, 2
and 2a). These are the external gills. In a few days the
mouth breaks through, and the animal begins to nibble at
the vegetation with little horny jaws, and soon swims about
the aquarium with confidence.

The gills are the organs by which the young tadpole
breathes, and each little gill-thread is seen, when viewed with
a low power of the microscope, to contain ^iny loops of
blood-vessels. Every time the tadpole uses his jaws, wags
his tail, or, in short, does anything at all, he uses up some

THE TADPOLE

345

oxygen and produces some carbon dioxide. The water of

the aquarium contains dissolved oxygen — green water-weeds
are kept m aquaria for the express purpose of liberating

oxygen (p. 51) — and this oxygen makes its way through
the excessively thin membrane which divides the blood of
the gills from the water, to be swept away by the current of
the blood to the various parts of the body. The carbon

346 AN INTRODUCTION TO NATURE-STUDY

dioxide produced is brought to the gills by tbe Mood stream,
and passes through the membrane into the water, where it
is utilised by the water-w^eed as food (p. 51). Animal and

plant are thus mutually serviceable.

A series of slits roon opens through the sides of the neck,
and along their margins are formed folds which are usually
called the internal gills. The external gills dwindle and
shrivel up as the internal gills are being formed, and at the
same time a flap of skin grows backwards from each side of
the head and covers over the slits so that they cannot be
seen. Presently the two flaps fuse at their edges — except
at one point on the left side, where a spout is left — and
so enclose a chamber. The water which enters the tadpole’s
mouth pours thtvugh t\w gill -slits, into the chamber, and
out through the .^\)ut. As it swills over the folds of the
internal gills there is an exchange of carbon dioxide for
oxygen in the manner just described.

The tadpole in tfie meantime is growing strong and
active, and the tail has grown out to* form a powerful
organ, the sinuous motion of which propels the animal with
relatively great speed through the water.

From the point of view of the biologist, perhaps the most
interesting feature of this stage of tadpolehood is the almost
entire correspondence of the structure with that of a fish,
although the adult frog is not in any sense a fish. This
curious state of things is explained by supposing thaf frogs
have descended from fish-like ancestors, and that every frog,
in the course of its development, is under the necessity of
repeating, in a more or less modified manner, the chief
stages of its ancestral history. As Marshall happily ex-
pressed it,i a frog during its development climbs up its own
genealogical tree.

The metamorphosis. — Just as the external gills are
^ Marshall’s The Frog (Smith, Elder & Co.).

THE TADPOLE

347

replaced ipternal gills, so these, in their turn, are
replaced by lungs, and advanced tadpoles frequently come
to the surfece of the water to breathe air. Limbs have now

grown out from the sides of the body, and the webbed hind
feet considerably assist the tail in swimming. Changes take
place in nearly all the internal organs, fitting the animal for
its life on land ; and these changes are so extensive that
there is necessarily a short period when the creature is
neither tadpole nor frog, and is incapable of feeding. The
tail, however, which would be useless to the terrestrial, leap-
ing fro^, is gradually absorbed, and forms a store of nutriment
during the transformation.

The gills shrivel up, and the slits close ; the outer layer
of the skin (including the horny jaws)ji thrown off, the
hind limbs lengthen, and the animal >eaves the water— a
frog.

EXElgLCISES ON CHAPTER XVIII.

1. Make observations upon toads. In what respects do they differ
in appearance from frogs ? How do they move about ?

2. Are the skins of toads dry or moist ? In what situations have you
found toads ? How do they protect themselves from the heat of the
summer sun ?

3. At what time of the year, and in what places, do toads lay their
eggs ? Compare the voice with that of a frog. Do toads inflate any
part of the body when they sing? Compare the vocal sacs with those
of frogs.

4. Look for toad-spawn in the spring. It forms long, gelatinous
ropes in which the eggs arc embedded. How large are the eggs ? In
what respects do they differ from frogs’ eggs ?

5. Keep toads' eggs in an aquarium, and carefully compare all the
stages of development with those of the frog.

6. Count h(TW many caterpillars you can persuade a toad to eat ** at
one sitting.” What would be one result of the extermination of toads
and frogs ? ,

348 AN INTRODUCTION TO NATURE-STUDV

7. Describe carefully what happens when a frog leaps, » Point out the

special arrangements which enable a frog to leap safely. (1897)

8. Describe the ordinary process of feeding of a frog, an^ show how

it is assisted by the peculiar structure of the frog’s mouth and tongue.

(1895)

9. Explain the special use of the wide gape of the frog. Where are

the teeth of the frog situated ? (1898)

10. Mention some remarkable features of the mouth of a frog, and

try to show that they are adapted to meet special needs. (iQOl)

11. Describe the process of filling the lungs with air, as observed in

the frog and the rabbit. (1896)

12. What changes take place in a tadpole during the first week after

hatching? Illustrate your answer by drawings. ' (1898)

13. Describe the appearance of one of the gills of a very young tad-
pole as seen Viy a lovvmagnifying glass. (190 1)

14. Describe the aWiearance, size, and mode ot liie of a tadpole

about a fortnight after hatching. On what does it feed ? Describe its
mouth carefully. (1897)

15. Compare a fresh-hatched tadpole with one in which the hind

limbs have recently appeared. (1898)

16. Trace the history of a tadpole from hatching to the time when
the tail begins to grow less. What does it feed upon during this time ?

(1898)

17. Relate the life-history of the frog, from the time of hatching to

the end of the first summer. (1897}

18. Give some account of the habits of a young tadpole a few days

after hatching, cspecirtlly with respect to locomotion and feeding.
Make a drawing of such a tadpole in side view, three times the natural
length. (1904)

19. Describe the hind leg of a frog, and explain the ways in which

it is u«ed. (1905)

20. Show how a full grown Irog is enabled to live either in air or in

water. ( J 906)

CHAPTER XIX.

THE HABITS AND LIFE-HISTORIES OF COMMON
INSECTS.

62. THE COCKROACH: A TYPICAL INSECT.

1. Habits. — In what places have you se^cockroachcs? Are
they often to be seen during the day, or do they, in general,
come forth only at night? What is the colour of the body?
Put a live cockroach under a tumbler, ai^d watch its movements.
In what position is the head held? Notice the long feelers \
how are they used? Look at the lower part of the head, and
try to see the fialps^ which resemble small feelers. How many
legs has the cockroach? Watch the rhythmical movement of
the hinder part of the body. Soak a small piece of bread in
milk or water, and put it under the tumbler ; watch the cock-
roach feed. How does it use the palps? Notice that the jaws
move from side to side. How does the insect clean itself?

2. External cbaracters. — Put a cockroach into a test-tube, and
dip the tube into boiling water ; this kills the insect instantly.
Notice the thin “shell” which covers the outside of the animal.
Make out that the body consists of (a) /leaf carrying the eyes,
feelers, and jaws ; (^) t/iorax^ carrying the wings and legs ; and
(i.) abdomen. Examine them in turn.

{a) The head . — Notice the vertical position, the black, kidney-
shaped eyes., the feelers., the “upper” lip {labrum\ and the small,
blackish mandibles at the sides of the labrum. Pass your knife-
point close behind the labrum and into the mouth, and see the
“ lower” lip (labium), which lies behind the knife, ix. behind the

350

AN INTRODUCTION TO NATURE-STUDY

mouth. Cut off the head .and carefully strip, off the labium.

Put it on a sheet of paper and examine it with a lens, compar-
ing it with Fig. 222 Examine the same; head from

behind with aliens and See the pair of first maxillae. Notice
bow they are attached to the head, and then remove one and
compare it with Fig? 222 (A/.r. i). Work one of the mandibles
backwards and forwards with the point of a pin, and then
remove it and examine it with a lens to see the toothed inner
margin.

(h) The thorax. — Notice the overlapping fore- wings {nving-
covers). Pull them aside with forceps ; notice that they are
narrow and rather stiff, make out their points of attachment at
the comers of Jhe second segment of the thorax, and then cut
them off with scissors. Pull out the delicate hind- wings in the
same way, careful^ noticing their fanlike method of folding, and
their points of attachment to the corners of the third segment
of the thorax. Str^uh one out, cover it with a piece of glass to
flatten it, and then draw it, marking the lines of folding. (Notice
that some cockroaches of the common species found in kitchens
are destitute of wings', and have only very small wing-covers.
These are females.) After removal of the wing-covers and wings,
the three segments of the thorax are very distinct. Notice that
each segment bears a pair of legs, 'fake off one of the legs and
draw it. How many joints has it What is the use of its bristles?

(c) The abdomen . — Observe the line which runs along the
dorsal middle line of the abdomen ; this marks the position of
the heart. Examine the method of telescoping of the segments
of the abdomen, and the soft membrane which connects the
dorsal and ventral plates of each segment. Notice that the
abdomen bears neither wings nor legs. Observe the pair
of short palp-like bodies Fig. 223) at the end of the abdo-
men, and between them, in the male, a pair of more slender
styles. In the female observe the boat-shaped brood-cham-
ber'^ (Eig* 223, si. 7), on the ventral surface.

{d) The spiracles. — In the thin membrane between the dorsal
and ventral plates, at the junction of two abdomipal segments,
look for a small hole (spiracle) leading into the interior of the
body. How many abdominal spiracles can you find on each

THE COCKROACH

351

side ? Observe .the two larger spiracles on each side of the

thorax, between the first and second, and the second and third
legs.

What is an insect. — The word insect is so commonly

applied to animals having no claim whatever to the title,
that it is advisable to point out at once some of the features
which distinguish insects from other animals with which
they are often confused. Insects, spiders, crustaceans,
centipedes, and their near relatives, all have jointed bodies
and legs, which are covered by a continuous suit of armour
of a substance called chitin. In some cases, as in lobsters
and crabs, this is for the most part hardened by mineral
matter to form a stout shell, being soft and flexible only
at the joints where ease of movement Tequired. In
other cases the layer of chitin may rema^^^ thin and delicate,
and all gradations between the two extremes may be found.
Though soft where movement of one part on another takes
place, the chitin is always firm enougli, elsewhere, not only
to form a protection for internal organs, but also to afford
attachment to the muscles which move the body and limbs.
It is therefpre a skeleton, but as it is on the outside of the
body it is called an exoskeleton^ to distinguish it from the
internal skeleton (p 224) of the vertebrata. Animals such
as insects, spiders, centipedes, and crustaceans, which have
jointed bodies and legs, and are covered by a chitinous
exoskeleton, are called arthropods. Insects may be at once
distinguished from all other arthropods by ihe single pair of
feelers and the six legs. Many of them, but not all, possess
wings — structures which are found in no other arthropods.
Insects are always air-breathers when adult.

The cockroach. — 'Fhe cockroach is not a general favourite,
but it displgiys so well the essential features of insect
structure that it affords an excellent introduction to the
study of the more popular members of the class, which in

352 AN INTRODUCTION TO NATURE-STUDY

many respects are highly specialised It is also easily
obtained, and of fairly large size.

The body of the cocjkroach (Fig. 220) is very distinctly
divided into three regions: (i) the head (Fig. 221) which
carries the feelers, 'the eyes (ey,) and the jaws {ma?i , max>^
and max ?) ; (2) the thorax, separated from the head by the
slender neck, and bearing the legs and the wings; and
(3) the abdomen, which bears neither jaws nor limbs.

The head (Fig. 221) hangs nearly vertically from the neck.
The large, compound eyes (n'.) are somewhat kidney-shaped ;
the long, jointed feelers are set in sockets just below the
eyes. The front of the head is smooth and rounded ;
hinged on its lower edge is a flap which hangs down in
front of the mouth, and is called the labrum or upper lip.
Just behind the labrum, and attached to the side and front
plates of the head, is the first pair of jaws, the mandibles
{man.^ Fig. 221 ; Mn.^ Fig. 222); they work from side to
side, and their inner edges, which bite against each other,

THE COCKROAtH

353

are strongly toothed. The secona pair of jaws, called the

first pair of maxillae Fig. 221 ; Mx. i, Fig. 222) is

situated behind the mandibles. Each first maxilla consists
of a two-jointed base and two branches ; the inner branch
bites against the inner branch of the first maxilla of the other
side, while the outer and
longer branch forms the
maxillary palf^ which acts
as a small feeler. The two
second maxillae (the third
pair of jaws) are broadly
like the first maxillae, but
are partially fused to form
the labium or lower lip (Fig.

222, Mx, 2), which hangs
down behind the mouth. The
outer branches of the second
maxillae are called the labial
palps {Lab, Pal), T,t is well to
acquire clear notions of the
arrangement of the jaws
understand the great modification which the mouth-parts
of many other insects have undergone. It is important
to notice that the jaws of all arthropods work from side to
. side, not vertically as do the jaws of vertebrates.

The thorax consists of three segments, each of which
bears a pair of legs, upon which the weight of the resting or
walking insect is supported. It has been found, by
instantaneous photography, that in a walking/ insect the
weight is carried at any instant by the first and third legs of
one side and the second leg of the other side. At the next
step the body is carried by the remaining three legs. In
the Americafti (Fig. 220) and German cockroaches both
sexes possess two pairs of wi%s, which are fixed ,at the
N.S. Z

Fig. 221.- C'ockroach. The head and
its appendages seen from the left side.
cerv,, one ot the neck-plates ; ej/., eye 'y.
gen., side^^late of head ; man , mandible ,
first pair of maxillae ;
second pair oi maxillae (labium), (x 5.>

in the cockroach, in order to

354

AN INTRODUCTION TO NATURE-STUDY

front angles of the second and third segments of the thorax.
The hind-wings, which alone are used in flight, are folded
up fan wise when not in use, and are covered by the smaller
fore-wings, which are generally called the wing-covers. In

the common cockroach of this country, only the male has

Fig. 222. —Jaws of the Cockroach. Mn.^ mandibles ; Mx. i, first
pair of maxillae ; Mx. Pa , maxillary palp (outer branch); La,, Ga.,
inner branch ; Mx. 2, second pair of maxillae (labium) ; Lab, Pa . , labial
palp (outer branch) ; La., Ga., inner branch. (X8.)

well developed wing-covers and wings. In the female the
wing-covers remain small, while the wings themselves have
disappeared.

The abdomen consists of ten segments, although only eight
can be clearly seen without dissection. The “ telescopic
arrangement of the segments is well shown in Fig, *223.
Where one segment joins the next, the chitin remains thin
and flexible. In each segment the chitin forms a dorsal
(p. 2 17) and a ventral plate, which are joined together at the
sides by a flexible membrane. The chitinous covering of

355

THE COCKROACH

the upper surface of the abdomen is so transparent that

the heart, a median tube, may be seen through it.

How an insect breathes.— If the^ sides of the abdominal
segments be carfully examined, a small aperture will be seen

perforating the thin layer of chitin between the dorsal and
ventral plates, at the point where each Segment joins the
next ; and, in the thorax, larger but similar openings will be
found on each side between the first and second and the second
and third legs. These holes are called Bpiracles (Fig. 223,
spir) \ they lead into a complex system of air-tubes which
ramify throughout the whole system and supply the organs
withox3^en. The tubes are prevented from collapsing by a
spiral lining thread of chitin. This peculiar method of re-
spiration, which is characteristic of insects, should be care-
fully contrasted with the manner of breathing in a rabbit or
a man (p. 242) and in a tadpole (p. 34$). It ought to be
borne in mind, however, that the essence of respiration is
the same in all living things, and consists in a replacement
of excess carbon jdioxide by fresh oxygen (p. 242) j the
difference lies merely in the manner of effecting the
exchange. In the rabbit, the blood, carrying the excess of
carbon dioxide, is brought to the air (in the lungs) ; in the
tadpole it is exposed, in the gills, to the dissolved air of the
surrounding water ; while in the cockroach the air is
carried directly to the tissues needing fresh oxygen. I'he
air of the tubes is renewed by a rhythmic action of the
abdomen, which can readily be observed in the living
insect.

Tlie internal organs. — Figs. 163 and 223, which represent
a general dissection of a frog and of a cockroach respec-
tively, exhibit in the most striking manner the essential
differences in the structure of vertebrates and arthropods.
The fact that the skeleton of the frog is wholly internal and
that of the cockroach wholly external, has already been

356 AN INTRODUCTION TO NATURE-STUDY

Fig. 223. — Cockroach ; general dissection of female from the left side.
abd, 1, first, and ahd. 5, fifth abdominal segments ; bm,, “brain err.,
cercus ; c.gl., glands which form the egg-case ; er., crop ; f., feeler ; giz.^
gizzard; gul.^ gullet; int., intestine; lab. ^a., labial palp; mx. pa.,
maxillary palp ; «, «, nerve chain ; r. ov., right, and /. 07 f., left ovary ;
sal. du., salivary duct ; sat. gl., salivary gland ; spir., spiracles ; st. 7,
Lrood-cnamber ; tk. i, first, ik. 2, second, and //t. 3, third thoracic seg-
ments. (X 2.)

SO called brain which is connected with the ventral

chain by a ring surrounding the gullet (gu/.). The heart
of the frog is ventral to the digestive canal; that of the
cockroach is the most dorsally placed organ of the body.

Habits and life history. — Cockroaches infest kitchens
and pantries ; they are of social habits, and hide together in
crevices during the day, but come forth at night to feed.
They are not at all fastidious as to diet, but are especially

A WATER BEETLE

3 S 7

fond of starchji^ foods, which they are able to digest

(p. 234) by means of the fluid formed in their large salivary

glands (Fig. 223, saL gL). The •eggs are laid sixteen at
a time in a little oblong case, which \he female carries about

in a boat-shaped receptacle (st. 7, Fig. 223) at the end of
her abdomen, until she finds a suitable place in which to
deposit it. When the little cockroaches hatch, they are quite
white, but except for the absence of wings they closely
resemble the parents in form, and run about and feed
freely from tl]e first. The chitinous exoskeleton is shed
from time to time as the animal increases in size, a- new
coat, a? first soft and wrinkled, but rapidly stretching and
hardening, having previously formed beneath the old one.
Shortly before the last moult, tfee wing-covers and wings
begin to grow out from the angles of the second and third
thoracic segments. In this manner the young animal
gradually takes on the fotm and dimensions of the adult.

The position of the cockroach in the insect class. — The
cockroach is famiHarly known as the “ black-beetle, but the
name is a very misleading one, because the true beetles differ
from cockroaches not only in structure, but also in life
history. Cockroaches are grouped with earwigs, grass-
hoppers, crickets, and locusts in the order Orthoptera,^ a
term alluding to the fanlike folding of the hind-wings.

63. A WATER BEETLE.*

r. The habits of Dytiscus. — Search a pond for water beetles.
I?ut them in a wide-mouthed bottle with some of the weeds to
be found in the pond, and take them home and observe their
habits. Among the larger beetles — especially from ponds with
a clear surface (not covered with duckweed, etc.)— will probably

^ Greek : orthos, straight ; pteron, a wing.

2 See Foot-note, p. 372.

358 AN INTRODUCTION TO NATURE-STUDY

be seen some with a yellow band round the edge of the upper
surface. These are Dytisci, Notice the ovoid, smooth body, the
breadth of the hind legs, and—in the male— the cup on each fore
leg. Try to see how the kgs of each pair are used. On what does
the animal feed? Take a small piece of meat in a pair of forceps
and hold it near the' beetle’s head. If the animal does not notice
it, stroke one of the feelers with the meat ; how does the beetle
behave? What is the use of the feelers? Noticehm^he
beetle rises to the sur face immediately it stops paddT iffg 7 ~"Which
€n<l ot the body sTicks out of the water ? Why does the beetle
need to come to the surface? In April look for larvae (Fig.
224, A\ and describe their appearance and habits.

2. External characters. — Kill a Dytiscus by dropping ^it for a
moment into boiling water. Examine it first from the dorsal sur-
face, noting the almost unbroken oval outline, and the firmness of
the armour. Notice that the inner edges of the two wing-covers
fit closely together xa the middle line. How does the beetle
compare in this respect with the cockroach ? Observe the small
triangular plate between the anterior ends of the wing-covers ;
open out the covers and wings to find of which segment of
the thorax it is a part. Examine the wing-covers and wings
closely ; notice that the wings are folded transversely as well as
longitudinally. Spread and pin out one wing-cover and wing of
one side, and draw a dorsal view of the animal Dissect out
the jaws and compare them with the jaws of the cockroach
(Fig, 222). Examine and draw one leg of each pair.

The bordered little diver. — In nearly every English pond
there at times occurs a beetle— an inch or more in length —
which is known to naturalists as Dytiscus marginalis. The
name is somewhat cumbrous, but it would be difficult to find
a more appropriate one; for “bordered little diver'' — the
plain English of the scientific term — indicates at once the
peculiarities which soonest strike the observer : the creature's
skill in diving, and the yellow band which runs round the
edge of the olive-green body. The outline of the beetle is
an almost unbroken oval, and it is worth noticing that either

A WATER BEiA'LE

359

such a boat-shape (Fig. 224, B\ or the cigar-shape of the tor-

pedo is adoptefl by ^Imost all actively swimming aquatic

animals. The resistance of the watof is further lessened by the
smoothness of the beetle’s armour, which forms a hard shell

enclosing the body. As in all insects, the body is divided
into head, thorax, and ab-
domen. The eyes are large,
and are so arranged that
the animal can at the same
time see objects both above
and below — a great advan-
tage to*a creature living so
active life. The feelers
are very sensitive organs of
touch, and possibly of smell
also. The jaws consist of
one pair of mandibles and
two pairs of maxillae, and
are shaped much Jike those
of the cockroach ; they are
powerful, and render Dytiscus a very formidable enemy to
the more peaceable inhabitants of the pond.

The thorax consists of the usual three segments, but only
the first and a small triangular area of the second are to be
seen until the wing-covers are pulled aside. These last
differ from the wing-covers of the cockroach not only in
being much harder and stronger, but also in their inner
edges meeting accurately along the middle line of the body.
The delicate, filmy wing.s, which alone are of use in flight,
are folded transversely as well as longitudinally. On the
lower side of the thorax are three pairs of legs ; they are
very interesting and are worth examining in some detail.
In the male', the first leg on each side is furnished with little
circular areas which were at one time believed to be suckers.

Fu;. 224. — A beetle of the Dytiscus
family. larva; />’, adult insect (male).

360 AN INTRODUCTION TO NATURE-STUDY

It is now known, however, that they give off a sticky ^
substance which adheres firmly to any .object clasped by the

legs. The middle pair df legs seems to be used; chiefly for

steering. In both sexfis the third or last pair of legs is
modified to form a pair of sculls. Ordinary land-beetles can
move their legs m a vertical direction, as well as in a
horizontal one ; but the hind legs of water-beetles are jointed
to the thorax in such a manner that they can only move back-
wards and forwards, not up and down. The resemblance of
the hind leg to an oar does not stop here, however. On one
side there is a fringe of stiff hairs, forming the blade of the oar.
The joint carrying the hairs is so arranged that the beetle
can “ feather ” its oar — by turning the edge of the blade to
the water — at each stroke.,

Occasionally, usually after sunset, the beetle quits his
watery home, and wheels* his droning flight ” in search of
pastures new. His flights are, ho\Yever, only temporary and
merely from one pond to another. Although Dytiscus thus
normally lives in water, very cursory observation only is
needed to see that he c annot e _xi st without a regular ^s upply
of fresh air. He no sooner stops paddling than his body
rises naturally to the surface, and as the tail is lighter than
the head, it rises out of the water. The wing-covers are now
raised a little, so that the space between them and the wings
is put into communication with the outside air. The
impure gas contained in this space is soon replaced by
a bubble of fresh pure air, the wing-cases are lowered,
and the “ little diver ” plunges oncfe more into the
depths. The water is prevented by hairs from getting
into the air-space below the wing-cases, and the true wings
are thus kept always dry. The spiracles (p. 355) are
in communication with the air-space, so that the aniirial
is enabled to remain below the surfai;;;^ for a relatively
long time.

THE LIFE-HISTORY OF DYTISCUS

361

The life-history of Dytiscus. — In March or April the
female Dytiscus lays her eggs in slits which she cuts in
the submerged stems of pond-weeds, and the eggs hatch
in about three^ weeks. The creatu 1 *e which emerges from
the egg is of active habits, but is not at all like the
parent in appearance. A young animal which leads an
independent and self-supporting life, and differs markedly
in structure from the adult, is called a la^ a. Thus a
tadpole is a larval frog, and a caterpillar is the larva
of a butterfly or moth. The larva of Dytiscus when of
full size is about 2 inches in length. Like other larvae
of its fkmily (Fig. 224, A), it has six slender legs, which
serve both for swimming and for crawling over the bottom
of the pond, and its head is provided with a pair of sickle-
shaped mandibles, with which it seizes its prey. Each
mandible is grooved on its inner sid^, the groove being
converted into a tube b); a membrane which covers it, in.
The savage larva sucks the blood of ife victim until literally
nothing is left but* the shrivelled husk. At the end of the
Dytiscus larva's tail are two appendages which are fringed
with hair. When the creature wishes to breathe it comesjg
the surface, and the tip of its tail protrudes out of the water.
As each of the appendages just mentioned is pierced with a
hole which leads into one of the two main air-tubes of the
body, an interchange of vitiated for pure air readily takes place.

When the larva is about six weeks old, it leaves the pond
and buries itself in the soil on the banks. Its exoskeleton
is shed, and a thin, transparent layer of chitin — the “pupa-
skin*' — takes its place. In this condition the animal sinks
into a state of torpor, and apparently becomes as motionless*
as a mummy. In this resting stage it is called ^upn . The
ptf^l stage is necessary for the completion of the great
changes — commenced some time previously — which must
take place before the larva can acquire the structure of the

362 AN INTRODUCTION TO NATURE-STUDY

adult. The pupal stage lasts two or three weeks, and when

at last the creature emerges from its cell it is 'a beetle like its
parents. «

In consisting of three well-marked stages, the life-history

of a beetle thus differs essentially from that of a cockroach
All beetles agree with Dytiscus in this respect, though in
manner of life almost every conceivable variation is found.
The beetle-order of insects receives its scientific name —
Coleoptera ^ — from the sheathing character of the strong
and closely-fitting wing-covers. The wings themselves are
large, and folded in a somewhat complex manner. The
mouth parts greatly resemble those of the cockroach.*

64. BUTTERFLIES AND MOTHS.^

I. CaUbage-wliite b&aerfliea. — (a) The eggs. — In May or Sep-
tember, search the leaves of cabbages, turnips, and other crucifers
(p. 95) for the tiny egj^s of cabbage- white butterflies. Do the
eggs occur singly or in clusters ? Are they found on the upper
or the lower surface of the leaf? Cut off a piece of leaf which
carries eggs, put it under a tumbler, and examine it every day
until the larvae (caterpillars) emerge from the eggs.

{b) The lanm. — Have ready a breeding-cage,” t.e. a box
measuring, say, i8”x8"x6", one large face of which is of per-
forated zinc or fine wire gauze, and the other of glass ; the box
should be without bottom, so that it can be placed over a food-
plant. Put the larvae, with leaves of the plant on which they
were found, under the box, and observe them carefully. Re-
place all rotted or soiled leaves by fresh ones. It is best to
keep the food-plant in a bottle of wet sand inside the case ; the
leaves then remain fresh for several days.

' Describe the appearance of the caterpillar ; notice its general
worm-like form and absence of wings. In the head^ observe the

^ Greek : koleos, a sheath ; pteron, a wing. ,

^ Living eggs, larvae, and pupae of Lepidoptera may be obtained from
Mr. H. W. Head, Burniston, near Scarborough, and other dealers.

BUTTERFLIES AND MOTHS

363

small feelers, and watch the action of the mandibles in feeding.

Behind the head come the three segments of the thorax ; notice
that each ^ears a pair of short, joiflted legs. How many seg-
ments can you see in the abdomen ? *Which of the abdominal

segments bear legs or feet ? How do these differ from the
thoracic legs t Look for the spiracles (p. 3^5) at the sides of the
body. Which segments have spiracles 1 Kill a full-fed cater-
pillar by immersing it in methylated spirit, or by putting it into
a small box with a few drops of ether {a 7 nost ifijiatmnable liquid)
or chloroform. When it is dead, examine it more closely. Try
to make out the mouth-parts clearly ; they are best seen from
the back of the head. The labium (p. 353) is here represented
by a co*nical body called the spmncret^ out of which come the
silken threads used to protect the pupa.

(c) The pupa . — When the larva is full-fed, it seeks out a
sheltered place, and fixes itself in position by means of silk
threads which issue from the spinneret, ^le larval skin is shed
^nd replaced by a pupal skin, and the animal remains quiescent
until the change from lar\% to butterfly is complete. Examine
the manner of attachment of the pupa* to its support. Kill a
pupa by immersiorf in methylated spirit, or by dipping it for a
moment in boiling water ; carefully strip off the skin, and make
a drawing of the animal. Especially notice the arrangement of
the wings and legs.

{d) The imago or winged insect . — When the internal organs
of the butterfly are completed, the pupal skin splits, and the
perfect insect comes out. Look for pupae between September
and March, or in July, and try to see the transformation.
Notice the method of flight of the butterfly, and the position in
which the wings are held when it settles. At what time of the
day, and in what kind of weather, have you seen cabbage-whites
flying ? Kill a butterfly by putting it into a bottle containing
crushed laurel leaves, or a few lumps of potassiurh cyanide (a
deadly poison) wrapped in blotting paper, and examine it
closely.

(i) The head . — Notice the large, compound eyes, the knobbed
feelers, the long and coiled proboscis.^ and the labial palps (which
look like tusks).

364 AN INTRODUCTION TO NATURE-STUDY

(ii) The thorax.— T va true form of tlte thorajc and abdomen is

concealed by the hairs which clothe the body. Wet the body
with methylated spirit to make the hairs lie down. ^Notice that
the first and third segments of the thorax are very small, while

the middle segment, which carries the fore-wings, is large.
Observe that the fOre-wings are not modified into wing-covers,
but are, generally speaking, much like the hind-wings. De-
termine the sex of the specimen by means of Fig. 225. Notice
that, when you touch a wing, a little white dust comes off on your
finger ; the dust consists of very small scales. Do both surfaces
of the wings bear scales ? With a rather stiff camel-hair brush,
brush the scales from the wings of one side. What markings have
been removed, and what new markings have been made Clear, by
the removal of the scales ? How many legs has the butterfly ?

(iii) The abdomen. — Count the segments.

2. The tlget moth.— In eSrly summer examine lettuce, straw-
berry, and nettle leav\?s for “woolly bears”— the hairy caterpillars
of the tiger moth. Keep these in the breeding-cage with the
food-plants, and observe and desonbe their appearance and
habits. How do thej behave when alarmed ? Watch them
spin their cocoons (pupa cases) about the end of June, and
describe the process. Examine the pupa, and state in what
respects it differs from the caterpillar. About the end of July
watch for the emergence of the perfect moth.

Notice the position of the wings of a resting moth. Are they
held like those of a butterfly ? Kill and examine the moth, and
compare it further with a butterfly. Especially notice

(a) That the feelers of the tiger moth are not knobbed at the
ends, but are either thread-like (in the female) or comb-like (in
the male) ; and

(b) That a bristle at the base of the hind-wing hooks on a
catch in the fore-wing of the same side.

3. The vapourer moth. — About the end of June examine rose
trees, fruit trees, willows, oaks, etc., for caterpillars of the vapourer
moth. They may be recognised (Fig. 228) by the reddish warts
and the tufts of hair which stand out from varic)u,s parts of the
body. Notice that the taterpillars fall into two groups accord-
ing to size, being, when full-grown, about 2 in. and ij in. long

A TYPICAL BUTTERFLY

365

respectively. Keep th^ larvae in a breeding-cage until they

pupate and change into moths ; notice that the moths (the
females) which come from the large caterpillars have no wings ;
while the male moths, which are deri^ed from the small cater-
pillars, have well-developed wings.

A typical butterfly. — The great beauty of butterflies and
moths, and the ease with which the stages of their wonderful
life history can be followed, have made these insects
favourite objects of study among naturalists of all ages.

Among the commonest of butterflies are the well-known
cabbage-whites, the caterpillars of which work so much havoc
upon cfops of cruciferous plants (p. 95). The eggs are laid
in May and September upon the leaves, and soon hatch out
into small larvae called caterpillars^hich feed voraciously and
grow rapidly.^ The larval skin is shed fy m time to time as it
becomes too small. The caterpillar (Fig. 225, A) is somewhat
worm-like in appearance, iut insect characters may easily be
recognised in it. The /tead is small Ind shiny. It carries
six eye-spots, but the large compound eyes of the adult are
not yet visible. A pair of short feelers is present ; and the
mouth-parts are obviously comparable with those of the
cockroach, although the labium (p. 353) has become con-
verted into a spinneret^ which gives out the silk threads used
^pr the protection of the pupa. The mandibles, which are
used in gnawing leaves, are stout and toothed ; the first
maxillae are rather small. Behind the head come the three
segments of the thorax, each of which bears a pair of short
jointed legs ; wings have not, as yet, developed. The
abdomen really consists of ten segments, although only nine
can be seen without dissection. Segments 3 to 6 of the
abdomen bear short, unjointed legs called pro-legs or
cushion feet, and the last segment bears a pair of appen-
dages called the anal feet, Spiraclfes are to be seen on
the first eight abdominal segments. In the larva of the

366 AN INTRODUCTION TO NATURE-STUDY

green-veined cabbage-white, each spiracle is reddish and

surrounded by a yellow border.

When the caterpillar has attained its full si?e, it stops

feeding and seeks out a sheltered place— often a chink in a

wall. Silken threc^ds are given off by the spinnerets until
a little heap of silk is formed into which the hooked end of
the abdomen is fixed. Then a girdle of silk is made,

Fi(,. 225. -CabbaKe White Untterfly. larva; B, pupa; C, perfect
insect. (All X §.) (A’ and C from photographs by Mr. A. Flattens )

passed round the thicker fore-part of the body, and so
attached to the wall that the animal is supported in an
upright position. The larval skin now splits and is peeled
off, and the pupa, or chrysalis, stage (Fig. 225, B) is entered
upon. All the external parts of the butterfly are complete
at the time of pupation, but profound changes are still
necessary in the internal organs ; it is to allow these changes
to take place in tranquillity that the resting, or pupal, stage
is interposed between larval and adult life.

At last the new organs are ready for their work, the pupal
skin cracks, and the perfect insect (Fig. 225, C) emerges. The

A TYPICAL BUTTERFLY

367

head now carries a pair of large compound eyes, and two

slender feelers with knobbed ends. The jaws also have been

remodelled in accordance with 'the completely different

manner of life upon which the insect is now entering. The

mandibles are now only doubtfully recognisable ; the first
pair of maxillae are elongated and grooved, and are closely
applied to each other to form a long tube called the proboscis
(Fig. 226, Mx,i)^ which, when not in use for sucking up the
sweet juices of flowers, is kept coiled up beneath the head ;
the palps of the labium {Lab. Fa.)
project like tusks on the sides
of the head. I'he thorax is pro-
vided with two pairs of broad
wings, which are covered with*
minute overlapping scales— form-
ing a delicate bloom ” which is
readily detached by rougji hand-
ling. In many butterflies and
moths the scales -are gorgeously
coloured and arranged in sym-
metrical patterns. The name
Lepidoptera,^ which is applied to
this order of insects, was sug-
gested by the scaly covering of
the wings. When the butterfly is at rest the wings are either
fully expanded horizontally, or are held vertically over the
back, the upper surfaces of the fore wings being in contact.
The first segment of the thorax, which bears the first of
the three pairs of legs, is greatly reduced ; the third segment
also is but small.

In short, the whole organisation of a butterfly is definitely
adapted to the special duties which belong to this period of
its life. The growing stage is over ; the sole object of life is

^ Greek : lepis^ a scale ; f>teron, a wmg.

Fig. 226. — A, Head of a Lepi*
dopterous insect ; B. the labium ;
Ant., feeler; E. eye; Lab. /’a.,
labial palp ; Mjc. i, proboscis ;
Mjt. Pa., maxillary palp (mag-
nified).

368 AN INTRODUCTION TO NATURE-STUDY

now to seek a mate and— in the case of the female— to lay the

eggs in a place where the future larvae may find plenty of
food. Ease of locomotion and conspicuousness are secured
by the broad and brilKantly-coloured wings; the peculiar

manner of flight is considerable protection against the attacks
of birds ; large eyes aid in the recognition of the mate ; and
a concentrated and easily-digested food is supplied by the
nectar of flowers, and made accessible by the long, sucking
proboscis — the service of cross-pollination (p. 92) often being
unconsciously rendered in return for the sweet draught.

The common species of cabbage- white butterflies spend
the winter as pupae ; the perfect insects emerge in April,
lay their eggs, and then die. The caterpillars pupate and a
second generation of bv,tterflies appears, their offspring
reaching the pupa stage about the end of autumn.

Motl^ — Moths ^pass through a life-history which is
identical, in its broad features, wit|i that of butterflies. The
larva which hatches from the egg is a caterpillar, whose life
is spent in feeding and growing. At the same time the
external features of the adult are gradually taking form
under the skin. When at last the full larval pze is attained,
and a resting stage is necessary for the perfection of the in-
ternal organs, the caterpillar’s skin splits, and is shed, and the
animal becomes a pupa or chrysalis. A moth-pupa is generally
somewhat egg-shaped (Fig. 227), whereas the pupa of a
butterfly is usually conical, though there are many exceptions.

The winged moth, which at length emerges from the
pupal skin, differs from a butterfly in certain obvious
respects. Its body is usually broad and thick; its feelers
are either comb-like or thread like, not knobbed at the ends ;
the two,, wings of one side are in most cases secured together
at the base by one or more bristles on the hind-wing
hooking over a catch on the fore-wing ; in rest, the wings
usually slope and are not fully extended. Whereas

MOTHS

369

butterflies usually fly only in the sunshine, moths often

fly by night, and the flowers which night-flying moths
frequent for nectar are as a rule white and strongly-scented,

and close during the day. In finding their mates, moths

seem to depend largely upon the sense of smell, which is
probably lodged in the feelers.

The life history of a typical moth is well exemplified by
the Tiger Moth (P"ig. 227), which is easily reared in captivity.
The larva — often called the “ woolly bear,” from its thick
covering of hair — may be found in early summer on the*

Fig, 227. — Stages ofTigei Moth. W, Caterpillar, from left side ; piup'r
(lemoved from t .rroon), ventral view; C, perfect insect (female). (From a
photograph by Mr. A. Flatters) (x^,)

leaves of lettuce, strawberry, nettle, and other plants. It
pupates about the end of June, working its hair, together
with silk spun by the spinneret, into a cocoo??, in which the
resting stage is passed. About a month later the perfect
moth emerges; its fore-wings are beautifully mottled with
cream colour and chocolate brown ; the hind-wings are red,
with metallic violet spots. The feelers of the male are
comb-like, and are probably very sensitive organs of smell,
by means of which he seeks out his mate. The female’s
feelers are thread-like.

In the Vai)ourer Moth (Fig. 228), whose “looping” flight
may often be observed even in the streets of towns during
the day, the two sexes are remarkably different from each.

370

AN INTRODUCTION TO NATURE-STUDY

other. The male (C) alone can fly ; the female (fi) is
wiggless, and is confined for the whole of her short adult

life to the place where sht3 emerged from the cocpon. Here
she lays her eggs and then dies. Neither she nor her mate
is capable of feeding.

I.W.9

It would be difficult to find a more striking example of
the fact that the one duty of the adult moth is repro-
duction. The female vapourer is even debarred from the
privilege of choosing favourable places for her eggs ; but
^ a compensation for this dis-
A m advantage lies in the agility of

the larvae (//), which ^re able
to migrate without difficulty to
' another plant whenever food
becomes scarce. As Prof.
Miall remarks : ^ ‘‘ Whatever
larva can do for itself, the
^mogmph’by female Can safely leave undone;

but what «the larva cannot
-do, by reason of sluggishness or restricted diet, the parent
must provide for. Hence activity and intelligence in the
one lead to degeneration in the other. . . . Wings are to
insects what spores are to ferns, plumed seeds to dandelions,
and hooked seeds to burrs — a ready means of dispersal.”

Other insects. — Space does not permit of more than a
reference to other insects, and the work of this chapter is to
be regarded as the merest introduction to the study of this
fascinating class of animals. The chief remaining orders
are the Kooroptera, including May flies, dragon flies, and
cjtddis flies ; the Hemiptera, among which are included the
various “bugs,” water boatmen, plant lice, etc.; the Diptera
(two-winged flies), such as the house-fly, gnat, harlequin fly,
tiaddy-long-legs, etc.; and the Hymenoptm, including bees,
wasps, ants, gall flies (p. 146), and ichneumons. Many of

^ Injurious and Useful Insects (Bell).

EXERCISES

37 ^

these insects tave aquatic larvae which may be found in
ponds ; and their life-histories should be studied in aquaria

£Lnd careful notes made of the transformations.^

EXERCISES ON CHAPTER XTX.

1. Elxamine the following animals, and find out [a) which are
arthropods, [b] which are insects : tortoise, spider, grasshopper, lobster,
earwig, centipede. Give reasons for your conclusions.

2. Keep a grasshopper under a tumbler with a small sod of grass.
Observe its habits, and find out how it “chirps.” Compare its struc-
ture with that of the cockroach.

3. C(?mpare a cockchafer with a water-beetle. In what order of
injects would you place the cockchafer, and why ?

4. Compare other water-beetles with Dytiscus, and try to trace their

life-history. *

5. Observe the habits and examine the structure of the water-

boatman. What reasons can you find for excluding it from the beetle-
order ? ^

6. Examine a daddy-long-legs, and try to £nd the two stumps which
are all that remain o^ the hind-wings.

7. Look for “blood worms” (larvae of the harlequin fly) in horse-
troughs and sluggish streams in summer ; keep them in a saucer of
water with a few dead leaves. Observe their habits and describe the
appearance of the pupa. V\piat kind of insect emerges from the pupa ?

8. Keep caddis-worms in an aquarium and describe their habits.

9. Examine the leaves of stinging nettles for caterpillars in June, and
try to rear butterflies from them. Carefully notice from which kind of
caterpillar each butterfly is derived.

10. Look for caterpillars of the Privet Hawk Moth on privets and
lilacs on August and September evenings. Keep some, with earth
and twigs of the food plant, in a covered flower-pot, and observe their
method, of pupation.

11. Compare the colouration of the wings ot butterflies and moths
with that of the plants they most frequent, and describe any cases of
protective colouration which you find.

^ MialPs lytjurious and Useful Insects (Bell), and Natural History
of Aquatic Insects (Macmillan), are strongly recommendtd as guides
to further work.

CHAPTER XX.

SOME CRUSTACEANS, MOLLUSCS, AND WORMS.

65. SOME COMMON CRUSTACEANS.

I. The crayfish and lobster. — (r/) Habits. — Readers in limestone
districts will probably be ab?e to find crayfishes in the streams,
and the habits of tl/^ animals in their natural surroundings
should be observed and described. Other readers will be able
to obtain live specimens from dealers?.^

Place the animal on fne table or desk. Notice that the body
consists of an anterior, unsegmented portion”, the cephahfhorax
(corresponding to the head phcs the thorax of an insect), and
a posterior, jointed abdomen. Watch the movements of the
stalked eyes, the feelers and legs ; allow the claws of the largest
pair of legs (the “pincers”) to grasp a pencil. Put the crayfish
in a white dish, with an inch or two of water, and by means of a
pipette discharge a few drops of water containing some sus-
pended colouring matter, such as carmine or indigo, near the
point of attachment of the last walking leg. Describe the move-
ments of the coloured water. When the animal is startled,
notice the sudden vertical flexure of the abdomen, by means
of which the body is pulled backward in the water. Feed
the crayfish with niCat or worms, and try to see the action of
the jaws.

{h) External characters . — Kill the crayfish instantaneously
by dropping it into boiling water. Compare the ‘animal with

^ Living specimens may be obtained from Mr. T. Bolton, 25 Balsall
Heath Road, Birmingham.

SOME COMMON CRllSTACEANS

373

,a cockroach (p. 349). Examine more closely the stalked eyes,
the two pairs feelers, the four pairs of walking legs and
the single pair of large pincers, and the fusion of the head and
thorax to fprm the cephalothorax. Count the segments of the
abdomen. *

ic) The appendages . — Examine the ventral surface of the
abdomen, and notice that each segment, (fxcept the last, bears
a pair of small jointed organs ; these are called swimviercts.
Remove one of the pair carried by the last segment but two,
examine and draw it ; make out that it consists of a stalk and
two branches. Notice that the branches of the swimmerets
of the last segment but one aie expanded, and form, with tli?
last segment, the tail fin.

Stud^ the appendages of the cephalothorax from behind
forwards. They consist of (i) four pairs of legs used for
walking, and a larger pair of pincers ; (ii) three pairs of foot-
jaws or maxillipedcs ; (iii) two pairs of maxillae ; (iv) one pair of
mandibles ; (v) two pairs of feelers. ^

• fi) The gills .— strong scissors cut off the side part of
the exoskeleton of the cepkalothorax, and notice the plume-like
gills in the gill-chamber thus laid opeft. Move the adjoining'
legs, and see that some of the gills also move.

2. The crah. — Obtain a crab and compare it, point by point,
with the crayfish, or lobster. Notice the great width of the shell
of the cephalothorax ; much of this width is due to the gill-
covers, which stand out from the sides of the true body. Look
for the opening of the gill-chamber at the base of the pincers.
•Make out the stalked eyes (in sockets), the two pairs of feelers,
and the five pairs of legs. Notice how the animal runs ; in
what respects does the method differ from the gait of the
crayfish Examine the ventral surface of a dead s])ecimen, and
notice that the abdomen is tucked under the cephalothorax.
Stretch out the abdomen ; compare it with that of the craw fish,
and count the segments. Notice the absence of the tail fin ;
it is not required, as the crab does not swim. Extend the
abdomen, and make drawings of the animal (i) from above,
and (ii) from below, and label the parts. Carefully remove
the foot-jaws and the true jaws, and compare them with the

374

AN INTRODUCTION TO NATURE-STUDY

cotresponding appendages of the crayfish. With strong*
scissors cut off one of the gill-covers, and examine the gills.
Observe that in the crab the gills are not in any case attached
to appendages ; they all spring from the sides of thf body-wall.

Tabulate the respects m which you have found the crayfish
and crab (i) to agree with, (ii) to differ from, insects.

The student who has worked through Chapter XIX. will
at once recognise in a crayfish, or a lobster, an animal
possessing many features in common with the insects, and

c.th.

II.

Fig. 229.-“ Crayfish, .seen from the right side. The appendages are
numbered in Arabic and the abdominal segments in Roman numerals.
ani. I, first, and nut, 2, second, feeieis of the right .side ; cJh., cephalo-
thora.v ; E, eye ; gill-cover. (x§.)

will find it interesting to try to discover for himself why it is
not called an insect, but is placed by naturalists in a
different class. '

The crayfish. — The crayfish (Fig.. 229), ♦ or the lobster
(which agrees closely in structure with the crayfish), is
obviously an arthropod (p* 351), for it is covered by an
e.KOskeleton of chitin, and has hollow jointed limbs and a
segmented body. In these respects it agrees with the
insects. On the other hand, it plainly possesses at least five
pairs of legs, and has two pairs of feelers {ant. i and ant. 2,

THE CRAYFAh

375

Fig. 229), whereas no insect has more than three pairs of
legs (when adult), or more than one pair of feelers.

These differences are apparent, at the first glance, atid
closer exalni nation reveals even greater contrasts. The
three primary divisions of the body into head, thorax, and
abdomen, which are so characteristic of insects, are not
obvious in the crayfish ; for the head and thorax are here
fused into one mass, the cephalothorax ^ 229, r.//;.),

which i^"^ covered by a shield called the carapace. Moreover,
in the crayfish every ^

segment except the last p<^b’ gch. e

bears apair of appendages, ^
which vary in form in
different regions of the
body according to their
duties, but which can
all be shown, by careful "

comparison, to be modi- Fig. 230.— Cnixfish ; ihe right giil-i'hamberaiid

r gills as seen after removal of (lie gill-

fications of one pymitive cover. rr., feeleis; 0-13, sixth to thirteenth
form, which is A-shaped

and consists of a basai M U, '(iili lo

stalk and two branches, twelfth appendage; PUk 13 gill on body-wall
above thirteenlli appendage. (Slightly reduced.)

This form of appendage

is well seen in the swimmerets (17, Fig. 229) of the abdo-
minal region ; further forwards the appendages become
walking legs (9-13, Fig. 229); next come three pairs which
combine the characters of legs and jaws, and are called
Thaxillipedes (S, Fig. 229),* then are lhc‘ true jaws— two
pairs of maxillae, and one pair of biting and crushing
mandibles ; and lastly, in front of the jaws, two pairs of
feelers (ant, 2 and ant. i). It is believed that the first pair
of feelers corresponds to the single pair of feelers of the
cockroach * that the jaws correspond to the jaws ; that
^ Greek, kephalon, a head.

370 AN INTRODUd'riON TO NATURE-STUDY

the nnaxillipedes of the crayfish are the equivalents of the
walking legs of the cockroach ; while the renlaining appen-
dages of the crayfish have no representatives in the insect.

Lastly, the crayfish differs essentially from the insect in
its method of respiration (p. 355), for it is an aquatic
animal and breathes dissolved oxygen. It therefore
possesses neither lungs nor spiracles but gills (Fig. 230),
I'hese are situated at the sides of the true body-wall, in gill-
chambers formed by the downgrowth of the sides of the
,^arapace. The gills are delicate plumes, containing fine
blood-vessels, so that an exchange of gases readily takes
place between the blood and the surrounding water. On
each side, a scoop (Fig. 230, ep, 5) on the second maxilla
is continually baling watgr out of the front of the gill-
chamber, fresh water flowing in from behind to take its place.
Certain of the gill^-*are attached to the legs, so that the
motion of the legs also is some assistance to respiration.

The crab (Fig. 231)3 is markedly different in shape from
the crayfish or lobster, but is nevertheless easily seen to

Fin. 2:^1.— Cr.ib : from above, B, fjoni below. an(~ i, first, and
ant. 2, >.ec-ond feelers ; abd. 3, third, and abd 7, seventh abdominal
segments; A, eye; L i, pincers; /. 5, last walking leg; vtxp., thiid
maxilbpede. (x^.)

be built on essentially the same lines of structure. It also
consists of twenty segments, of which the first, thirteen are
fused to form a cephalothorax ; and the appendages of this

THE WOOD-LCJUSE

377

region are quite comparable with those of the crayfish. The
great width of the shell is largely due to the gill-covers,
which stand out from the sides qf the body much further
than do thbse of the crayfish. As«a result the crab finds it
easy to run side-first. The crab is essentially a walking,
not a swimming, animal, and the abd^imen — upon which
the crayfish and lobster so much depend in swimming — is
in the crab reduced in size and kept tucked under the
cephalothorax.

Crustaceans. — These facts are sufficient to show that
title “insect” cannot with any propriety be given to either
the crayfish or the crab, unless, indeed, the term is to be
applied to all arthropods indiscriminately. The crayfish,
lobsters, shrimps, prawns, crabs, barnacles, and many less-
familiar animals, are placed in the crustacean class of arliiro-
pods. Crustaceans have usually a di^inct
head, thorax, and abdomen ; but some of
the thoracic segments may be fuse<j with
the head to form, a cephalothorax (p. 375).

Like other arthropods, the animals are
covered with an armour of chitin, and in
many cases this is so hardened, except at
the joints, by mineral matter that it be- woodi>u7e. "(>! 1'.)

comes a rigid shell or crust. The head
bears two pairs of feelers in addition to the jaws ; and the
segments of the thorax and abdomen are provided with
appendages which are variously modified as jaw-feet, legs,
swimmerets, etc. Typically, the animals breathe by gills
and are aquatic, but forms are known which are able to live
comfortably on land if the gills are kept moist One of the
most interesting examples of this is found in the common
wood-louse (Fig. 232), which lurks under stones and logs in
damp and* dark situations, and breathes by plate-like gills
on the abdominal segments.

378 AN INTRODUClriON TO NATURE-STUDX

Other arthropods. — Other familiar arthropods, which are
neither insects iior crustaceans, are spiders 'and centipedes.
I'he spiders belong to th^i arachnid class, and the centipedes
to the myriapod class of>arthropods.

66. SOME COMMON MOLLUSCS.^

I. The fresh-water mussel.— O) Habits. — Study the habits of the
living animal (Fig. 233) in the aquarium. Notice the muscular
.foot which is protruded between the halves {valves) of the
shell, and by means of which the mussel slowly makes its way
along the sandy bottom. With a pipette, discharge some water,
coloured with carmine or indigo, close to the more pointed end
of the shell. Where is the coloured water taken in, and where
is it expelled ? Notice thatf'^he shell closes when the animal is
handled.

{b) The regions of ffje shell. — The rounded end is anterior, the
more pointed end posterior, the straight hinge-line dorsal, and
the gape ventral, Notjee the knob-like umbo on each side near
the anterior end of the hinge ; it is the oldest part of the valve.
Make out the concentric lines of growth, showing the successive
positions of the margin. Draw the shell from the right side and
from above.

{c) General structure. — Kill the mussel by putting it for a few-
minutes into hot, but not boiling, water. Notice that the valves of
the shell now gape apart somewhat. Hold up the animal and
see, lining the shell, a thin soft membrane, the mantle. Carefully
separate the mantle from one valve and notice, near^each end, a
thick white pillar which passes from one valve to the other.
These pillars are the closing muscles. Pass the blade of a knife
between the mantle and valve, and cut through each closing
muscle quite near to the valve. Curn the valve back and
remove it from the other valve by cutting through the elastic
ligament (at the hinge) with strong scissors. Clean the inside
of the separated valve and examine it ; notice (i) the line of
attachment of the mantle ; (ii) the impressions 01 the closing
' ^ See foot-note, p. 372.

SOME COMMON MOLLUSCS

379

muscles ; (iii) the lines of shifting of the closing muscles —
triangular depressions stretching from the umbo to the muscles.

Examine the animal as it lies in the other valve. Make out :
(i) The righjt and left lobes of the 7nh7itle whicli line the valves
and (in the natural position of the mussel) hang down from
the sides of the body ; (ii) the two plate- like gills on each side,
lying between the mantle and the foot ; (il*i) the median foot ;
(iv) the reddish, triangular palps surrounding the mouth— an
aperture at the anterior end of the foot. Push a stout pin into
the mouth and upwards into the gullet. Make a drawing
showing the relative positions of the parts.

2. The garden snail. — [tx) Habits. — Where have you seen snailff

At what time of the year are they most active.^ Upon what do
they feed ? Place a snail upon a lettuce leaf and carefully watch
its method of eating. How does it move about? Put a live
snail upon a sheet of glass, and look through the glass to see the
wave-like action of the flat sole - the foot — by means of which
it moves. ^

Have you ever found snails in winter? How much of the
animal was visible ? Ho\f is the mouth of the shell closed in
winter ? *

(b) General appeara7tce . — Make a di awing of the animal
from the left side and another from the right side, and notice
the differences between the two. Is the shell placed over the
middle of the animal, or does it lie to one side ? How many
turns has the spiral of the shell ? In a fully expanded snail
observe the fleshy ‘‘ collar” round the margin of the shell ; it is
\he edge of the 7nantle. Notice the rounded head^ the two pairs
of tentacles, the eye-spot at the tip of each of the larger and upper
tentacles, the fnouth, and, near the base of the shell on the right
side, the respiratory pore, which opens into the hoig. Touch
various parts of the body in turn to see if they are irritable ; how
are the tentacles retracted?. Can the animal close and open its
respiratory pore at vvill ?

3. An air-breatliing pond-snail.— Obtain several fresh-water
snails and study their habits in glass aquaria. The commonest
fresh-water •snails are species of Lmmaea ; identify some of
these by comparison with Fig, 234, A, and try to make out the

38 o an INTRODUWION TO NATURE-STUDY

. ^ .

parts already seen in the garden snail. Watch the action of
the mouth as the animal feeds on the green scum which often
collects on the sides of aquaria. Notice how it creeps over the
glass or along the surface-film of the water. When the snail
comes to the surface it replaces the air of its lung by fresh air,
and a bubble may often be seen escaping from the respiratory
opening under the lip of the shell. Look for the spawn
masscs) of this snail on leaves or on the sides of the aquarium,
and examine the eggs frequently with a hand lens.

Molluscs.- Molluscs aie soft-bodied animals, in most
cases protected by a hard, external shell, but they differ

Fk;. 23^, -Fresh-\vater Mussel. A, from left side ■. />’. fiom behind.
//, foot ; /// .s//r., iuh.ilant siphon ; ex. exhdlant siphon ; liga-
ment ; ;>!, mantle , nniho. (aj ) (After Howes.)

essentially from (Tustaceans and all other arthropods in not
being segmented, and in not possessing jointed limbs.
Familiar and instructive examples of two classes of the
group are found in the fresh-water mussel and the garden
snail.

The fresh-water mussel (Fig. 233) is to be found in streams,
along the bed of which it ploughs its w^ay by means of a
muscular foot (//.). The body is enclosed in a brown

SOME COMMON MOLLUSCS

381

shell, which consists of halves called valves, hinged together
along the straight, dorsal edge by an elastic ligament
The action* of the ligament is to sej^arate the valves slightly
unless they are forcibly held together by the contraction of
closing muscles which run from one v^lve to the other
Hence the shell of a dead mussel always gapes open. I'he
rounded end of the shell is anterior, the more pointed end
posterior. The oldest part of each valve is the umbo (//w.,
Fig. 233), a knob just in front of the ligament ; and concen-
tric lines surrounding the umbo mark successive positions oT
the margin of the valve as the animal increased in size, d'he
valves are formed by the activity of the mantle lobes --
a pair of delicate membranes which hang down from the
sides of the body. The foot is a ftiedian prolongation of the
body itself, and on each side a pair <jf plate-like gills lies
between the foot and the mantle lobe of that side. “'Fhus
the whole animal has be^n compared to a book, the back
being represented by the hinge, the covers by the valves, the
fly-leaves by the mantle lobes, the first two and the last two
pages by the gills, and the remainder of the leaves by the
foot.’’ ^

When the living mussel is unciisturbed, the mantle folds
project slightly at the hinder end of the shell, their edges
being so placed in contact that they form two short tubes.
A current of water flows in at the lower of these (in. sph.^
Fig. 233), carrying to the mouth a supply of food-particles,
and to the gills and mantle a store of dissolved oxygen ;
while an outgoing current leaves by the upper tube {ex. sph ).

The garden snail (Fig. 234, B) seems at first sight to have
but little resemblance to a mussel ; but it also is a mollusc —
consisting of a soft, unsegmented body, which is produced
ventrally into a foot, and is protected by a shell formed by
the activity of a mantle fold of the body. In this case, how-
^ Parker and Haswell’s Text-book of Zoology (Macmillan).

382 AN INTRODUCTION TO NATURE-STUDY

ever, the shell is one piece, and is spirally coiled. The snail
has also a distinct head, which bears two pairs of tentacles ;
at the tip of ^ach of th^it)nger and upper tentacies (/) is an

Fig. 234.—'^, A Fresh-water Snail {Limnaea)\ Garden Snail.
e, eyes ; respiratory pore ; /, tentacles, (x i.)

eye ie). The animal crawls^about by wave-like contractions of
the muscular foot ; it{eeds upon vegetation, which it rasps into
small particles by means of a toothed tongue, and then swal-
lows. The snail is eijdrely adapteii to a terrestrial life, and
breathes air — the mantle fold under the. shell enclosing a

lung chamber with blood-vessels
in its walls, which opens to the
exterior by a respiratory pore
{p.o.^ Fig. 234) on the right side.
The snail spends the winter,
in a state of torpor, under logs
or stones, the body being en-
tirely retracted into, the shell,
the mouth of which is closed
by a plate of hardened slime.

Slugs (Fig. 235) are of very similar structure, but in them
the sheHi(| has almost disappeared, even the trace which
remains being concealed by the mantle fold.

Among the commone.st of fresh-water snails^ are various
species of Limnaea (Fig. 234, A). They may be found abun-
dantly in ponds, and are often kept in aquaria, where they

Fig. 235. —Slug,
pore, (xt.)

/.a., respiratory

earthworms

383

perform a useful service by devouring the minute plants
which are apt to accumulate to an undesirable extent and
form green scum on the sides. T hese snails^ like the gard en
sn ail^ breatfie air, and often come td the surfa ce to Uj Te a
f resh info~tFeir lung Siainbers. Some other water

snails, how^^, bfealHe by means of gills

beneath the shell.

67. EARTHWORMS.

1. External characters. — Dig up several earthworms from the
soil andexamine them. What is the length of the largest and
of the smallest specimens ? What is the thickness of the body ?
Watch the worms crawling about, and describe the method of
locomotion. Has the animal any*legs ? Do the length and
thickness of any one worm vary during its movements? Is the

.variation connected with locomotion? ifow? Can you dis^*
tinguish between the fore ^anterior) and hind (posterior) ends,
and between the upper (dorsal) and leaver (ventral) surfaces ?
How do they differ?

Kill a large worm by immersion in methylated spirit and
examine it more closely. Notice the segmented character of the
body, and estimate the number of segments. Which part of the
body has the largest segments ? Observe the swollen appear-
ance ot segments 32 to 37 ; this region is called the clitellum.
Notice the mouth (overhung by a short lobe) in the first segment,
and the vent in the last segment. On the ventral surface of
segment 14 try to see a pair of small pores ; these pores are
the openings through which the eggs are discharged from
the body. Pull the worm gently between your fingers, and
notice the bristly feel ; in which direction of motion is this
most apparent ? Examine the ventral surface with a strong
lens in a good light, and try to see four double rows of very
small bristles.

2. Habits. -^Examine the surface of the ground of a garden or
lawn at night by help of a lantern or lamp, being careful to tread
lightly, and observe the actions of any worms you see. Are

384 AN INTRODUdriON TO NATURE-STUDV

more worms to be seen at night than during the day ? Do the
worms seem disturbed by the light of the lantern ? Try to
grasp one ; is it easily caught? Why not? Where does the
worm retreat? If you can^grasp a worm before it«has time to
withdraw completely into its burrow, observe the difficulty of
drawing it out without tearing it. Try if the worms are
disturbed by a loud shout (be careful not to blow upon them
when shouting), or by a heavy stamp of your foot.

Carefully lay open several burrows and notice :

{a) Whether the mouths of the burrows are plugged in any
V v riy, and, if leaves are used for this purpose, whether the leaves
have been dragged into the hole (i) by the broad ends, (li) by
the narrow ends, or (iii) by the sides ; do you find acy signs
of intelligence in the method adopted?

{b) The length and width of the burrow^ and the character
of its lining. 0

(r) The end of the burrow ; is it enlarged ?

. Examine worm casf/^t^s. Mark out a square* yard of surface
and collect, dry, and weigh all the castings found on this area in
a certain time, say a m^nth. Such observations should be made
at different periods of the year, and over dilferenl kinds of soil,
and comparisons made. Estimate the weight brought up per
acre by worms during a year. Are the particles composing the
castings very fine, fine, or coarse?

Place worms in glass-covered flower-pots with earth of
different degrees of firmness, and observe the methods of
burrowing in loose and in firmly compacted earth respectively.
Place pieces of leaf of carrot, onion, and cabbage on the surface,
and at night observe hov/ the worms grasp the pieces and drag
them into the burrows.

Earthworms. — Few people except naturalists have any
idea of the vast number of earthworms living in the surface
soil of this and most other countries, or of the importance
of the work which they do.

d'he common earthworm (Fig. 236)is much simpler in struc-
ture than any of theanimals previously considered' in this book.
It is roughly cylindrical in shape, though somewhat flattened

EARTHWORM^

385

on the ventral surface. It is divided into about r5o seg-
ments, which are marked on the exterior by grooves running
round the body. The mouth is an. opening in the first seg-
ment (Fig. 236, 1 ) and is overhung by a short fleshy lobe. The
worm crawls along by alternate elongation and shortening
of its body, being aided by short bristles #which are directed
backwards and act as pivots ; limbs are entirely absent.
The animal is very sensitive to touch, even to the vibrations
of the ground ; but it is stone-deaf, only
just capable of distinguishing between
light and darkness, and has very little
sense r/f smell.

During the day, the earthworm gene-
rally remains in its burrow in the soil,
with its head just inside the entrance.

Its method Of forming the burrow de-
pends upon the texture of the ground.

In loose soil the earth is simply pus^ied
aside, but where the material is too
compact for this, the animal actually eats
its way through. The burrow is lined
with soft earth or little stones and is
plugged at the mouth with leaves or other convenient
objects. The animal was found by Darwin to display
distinct intelligence in its manner of drawing leaves into
the mouth of its burrow, seizing them in most cases by
their narrow ends, so that they could be pulled in with
as little difficulty as possible. Objects are generally
grasped between the lobe, which overhangs the mouth,
and the lower part of the first segment, the hold being
maintained by a sucking action. The inner end of

the burrow is enlarged to allow the worm room to turn
round. Ac night, the fore part of the body is protruded
in search of food, the tail being generally retained in

N.s. 2 B

side. 1, 35, jj, first,
fifteenth, Etnd tlurty*
tfurd segments. i )

386 AN INTRODUCTION TO NATURE-STUD,Y

the burrow, ready for instantaneous tetreat in case of
alarm.

The earthworm feeds upon leaves— -which are first
softened by a fluid discharged over them, and then sucked
into pieces small enough to be swallowed, for the animal has
po jaws— and upop the half-decayed organic matter which is
always present in ordinary soil. The soil itself is swallowed
in large quantities ; the nutritious portion is extracted, and
the undigested matter deposited upon the surface of the
ground, near the mouth of the burrow, in the form of
cajstiEgTB. As a result of numerous experiments, Darwin
estimated the weight of castings thus thrown up by earth-
worms on an acre of land as 1 5 tons annually. The follow-
ing passage is worthy of very careful attention : “ When we
behold a wide, turf-covered expanse, we should remember
that its smoothnes|^ on which so much of its beauty
depends, is mainly due to all the inequalities having been
slowly levelled by wonns. It is a marvellous reflection that
the whole of tlie superficial mould over, any such expanse
has passed, and will again pass, every few years through the
bodies of worms. The plough is one of the most ancient
and most valuable of man’s inventions ; but long before he
existed the land was in fact regularly ploughed, and still
continues to be thus ploughed by earthworms. It may be
doubted whether there are many other animals which have
played .so important a part in the history of the world as
have these lowly organised creatures.” ^

The earthworm lays its eggs in a small cocoon formed by
the hardening of a viscid material which is discharged by a
swollen part of the body called the clitellum, extending
from the 32nd to the 37th segments. After the formation
of the cocoon the worm moves backwards, and the eggs leave
the body by small pores on the ventral surface’ of segment
^ Darwin’s Vegetable Mould and Earthworms (Murray).

EXERCISES* 387

14, as this region passes the cocoon. A small amount of
food-material is also enclosed in the cocoon, and forms a
store of nutriment for the young worms during their early
development. ’

EXERCISES ON CHAPTER XX.

1. Compare the legs of a cockroach with those of a crayfish and a

vertebrate. * ( 1 900)

2. Describe the respiratory organs of the craytish. How are tli^ ^
continually supplied with fresh water?

3. ^ExJ^rnine a spicier. How many legs has it ? Of what divisions
does its body consist ? Why do you consider that a spider is not an
insect ?

4. Make obseivations, and write ^csciiptions, of the habits of
spiders, paying special attention to the methods of consiructiiui of the
webs, the manne? of catching prey in different #ases, and the care of the
young by the parents.

5. Compare a centipede wifh an insect, pointing out the features of

resemblance and difference. '* (1897)

6 . How does a pond-mussel open and close its shell ? (1900)

7. Compare an oyster with a fresh-water mussel, and try to find
points of resemblance and difference, making caieful notes and sketches
of these. How many closing muscles has the oyster ? Are its gills
plate-like? Why do you consider the oyster a mollusc ?

8. Where is the lung of a snail situated ? How do we know that it

is really a lung ? ( 1 897)

9. How does an earthworm resemble and differ from a catei pilkir ?

(1900)

10. Explain the action of an eaithworm in the formation of vegetable

mould. {1897)

H. Classify the animal described below :

A land animal with a long narrow soft body and no legs ; two pairs
of tentacles on the head ; a breathing hole on one side (1904)

12. Give the characters by which insects can be distinguished from
crustaceans. ‘ (1905)

chapter XXL

FIELD-WORK.

An animal or a plant must be studied from several poants
of view before its manner of life can be understood in
any real sense. It must, ^r exam})le, be regarded, first, as
a complicated piece of machinery, every part of which is
beautifully fitted foiv^ the performance of a ''special duty ;
it must also be considered as an individual^ Laving likes
or dislikes— or at lanst tendencies —which are to some
extent peculiar to itself ; finally, it must be considered in
its relation to other animals and plants, and to its sur-
roundings. Field-work is especially concerned with the last
of these methods of study— the observation of living things
under natural conditions,— and this ought constantly to be
borne in mind. To make nature-study a pretext for up-
rooting locally-rare plants and robbing birds’ nests is
indefensible. The commonest plants are usually the most
instructive, and afford ample material for the beginner’s
experimental work ; while the pleasure of finding and describ-
ing (perhaps photographing) a bird’s nest, and of keeping
the eggs and young under observation, is something un-
known to the mere collector of eggs. I'he life of both
plant and animal is sacred in the eyes of every nature-
student worthy of the name. At the same time, no
sentimentality ought to prevent the destruction of un-

FIELD-WORK

3^9

doubteclly noxigus insects and weeds. In general, however,
specimens should be killed only for the j)iirpose of a
leisurely e?^amination of structure,* wliich would otherwise
be impossil)le, or to make needed additions to the teaching-
collection of a school museum.

(Generally speaking, collecting is of very doubtful value,
except to experts. Insects and common })lants may, how-
ever, be collected without scruple by the beginner, though
it is worth remembering that the most perfect sjK'cimens
of butterflies and moths are those reared in captivity fr(fftfi-
the eg^s, larvae, or ])upa(i.

The student is strongly rec'ommended to make a sketch
map of some small area to which he has easy access, and to
record upon this the positions of#leatures of special interest.
Such a map may, in the first instance, be cojiied on an
enlarged scale from an ordnance map (Tf the neighbourhood,
whicli may be obtainecUat tht# local free library. It will
be advisable to duplicate the drawinf^ by means of one of
the many applianbes for such work, and to keeji one copy
each for trees, flowering plants, birds’ nests, etc. — the
position of each object, or of a well defined group, being
carefully marked by a small number (Fig. 237), and the
reference, with the date, being filled in on the margin, d'he
varying character of the ground — sandy, marshy, clayey,
etc. —should be indicated by diagrammatic shading or
colouring. By following this method the student wifi

more clearly realise that different plants are de[)endent
upon different conditions of soil, drainage, etc. ; and that,
e.g., plants at home on a bleak moor, in a hedge, in
marshy land or in water respectively, are characteristically
modified so that they can make the best of their siiecial
conditions pf life. In this manner he will, almost uncon-
sciously, gain wider views of the relationships which
exist between the facts learned from his more detailed

390

AN INTRODUCTION TO NATURE-STUD^

observations. It would be a distinct gain to biological
science if field clubs also would adopt some such plan,
each member undertaking to fill in upon his , map infor-
mation of the animal and plant life of the area allotted
to him. The co-operation of various clubs, and the
systematic arrangement of information thus obtained, would
result in a store of knowledge of the highest value.

Many animals are so shy that they can only be
approached with difficulty. In such cases it is especially
‘^iiccessary for the observer to move quietly and silently,
and, when a favourable position is reached, t<5 remain as
motionless as possible, preferably with his back to the
sun. If a field-glass can be obtained it will be of great
assistance, but some prafctice will probably be required
before it can be used easily.

It is well to start each ramble with some definite
object of study in view — either trees, grasses, flowers,
fruits, birds, caterpilla^rs, or pond life, for example, and to
be provided with pill-boxes, bottles, etc., according to
circumstances. A note-book, pencil, pocket knife, and
hand lens should, however, ahvays be carried, and
observations should be recorded on the spot.

Pond life. — Practically the only method of gaining a
real knowledge of aquatic organisms is by the help of
the aquarium. Specimens may be obtained by means of a
net, or of a small wide-mouthed bottle tied to a stick. A
pickle bottle is convenient for carrying home the material
collected. The conditions of a natural pond should be
imitated as closely as possible in the aquarium. At first,
some little difficulty will probably be found in obtaining the
necessary balance between the animals and plants of the
aquarium. When this has been reached, it will only rarely
be necessary to change the water, provided that- dead or
sickly specimens are promptly removed.

THE SCHOOL JOURNEY

391

THE SCHOOL JOURNEY.

In the organisation of school journeys so much depends
upon local conditions of various kinds, so much must of
necessity be left to the initiative of the teacher, that it is
manifestly impossible here to do more than enunciate
certain general principles. In the first place, it should
borne in mind constantly that the primary object of the
school journey is the cultivation of habits of thoughtful
observation ; and that the chief danger to be guarded
against is that out-of-focus condition into which the mind,
like the eye, inevitably falls when it is concerned with too
many things at once. To obviate thft, danger the teacher
should go over the rouie in advance, noting carefully the
features, physical and otherwise, whit'h afford material for
observation and Investigation by the class. The order in
which these features may be best studied should be decided
upon, and a scheme of several visits, each to be concerned
with one special subject of study, can then be drawn up.
Such a preliminary survey .should suggest a plan by which
«very member of the class may be allotted a definite task —
to find something or do something, or to solve some pro-
blem on the spot.

These principles may be be.st illustrated by a special
example, but it will be obvious that the same ideas, with
modifications in detail, may be applied in any district.
The sketch-map (Fig. 237) illustrates a walk through Healey
Dell, near Rochdale, Lancashire. The rocks which are
exposed at^ various places along the route belong to the
Carboniferous formation, and are composed of shale, coal,
or millstone grit.

302 AN INTRODUc'tION TO NATURE-STUDY

The object of the first journey will be in most cases to
familiarise the class with the lie of the land ” and the
most obvious features of the scenery. As a preparation,
lessons should be givei'j on the points of the compass and
the various methods of finding the direction of the north.
I'he simplest of tiiese is by the use of the compass : it
being remembered that the needle pointt> about i6° to the
west of true north. A second method dej)ends on the fact
that at noon the sun is in the south and that ^therefore
jji^^^cause the hour hand of a watch makes two revolu-
tions in the twenty-four hours) the north and south line
approximately bisects the angle between twelve and the hour
hand, if the latter is ]H)inted to the sun when the watch is
horizontal. Incidentally, (he method of finding the pole-
star might be also ex])lained to the class. Further, each
pupil should be enco iraged to find out how "fnany steps he
takes, on the average, in pacing a^given measured distance.
If the general directic^^i of the walk is north and south, as
in the example, it will be found best to begin the first
journey at the south end (in this case from Shawclough
Station), since to most children it is easier to conceive of
a journey nortliward than in any other specified direction.
Throughout the ramble constant reference should be made
to tlie direction of the route and the relative positions of
well-marked features of the? landscape. The distances
between certain points should be estimated, and, whenever
jiossible, measured (by pacing), and notes made by the
class. For example, from Shawclough to Ending the

Fu,. 2 37. — Sketch-map of Healey iJell, Rochdale.

I, birches ; 2, willows ; 3, beech ; 4, potholes ; two waterfalls ; 6, shallows, and
vertical concave hank; 7, Fait its’ Chapel”; 8, stratification of rocks; q, mud
deposits ; 10, waterfall ; ii, dork.--; 12, sloping trees; 13, weir; 14, railw-ay viaduct;
15, horse chestnut ; 16, aqueduct ; 17, sycamore ; j8, elm ; ig, elm 20, beech ; 21,
pond life ; 22, well ; 23, .shale ; 24. sycamore ; 25, oak, bearing leaves in winter ; 26,
flagstones ; 27, beeche.s, with wood-pigeons’ and magpies' nests ; 28, hawthorn hedge;
2g, solitary oak ; 30, gutter, with Fellia ; 31, blackberry bush ; 32, stunted oak.

Etuery Walker ic.

394 an introduction TO NATURE.STUD\^

distances and directions are roughly : ^rmile W.N.W.,
J-mile N.N.W., |-mile E.N.E. In the first journey also
the class should be made^to notice where the ground slopes
most and where least ‘(the direction and angle of slope
should be estimated in a few cases), and the names of
neighbouring woocfs, farms, etc., should be learnt. The
direction of flow of the river and the various bends in
its course should also be noted, and reference made to
the route by which, after joining those of other rivers, its
w/ers ultimately reach the sea. Afterwards, the pupils
should write an account of the journey and, in the higher
classes, should be encouraged to draw a sketcK-rfap,
however crude, from memory.

Before the second joumex; each pupil should be provided
with a blank sketch-map of the route. This may, in the
first instance, be cbpied or traced from^ the six-inch-
Ordnance Map, and then duplic<?ted in large numbers.
Only the route and civer, and a few of the more con-
spicuous landmarks, should be indicated" on the maps as
given to the class : details should be filled in, on the spot,
by the pupils. 'The object of the second journey may
conveniently be the study of the river and its work, and
for this purpose it will be advisable to follow the stream in
the direction of its flow. Variations in the speed of thei
current, and in the width of the stream and the hardness
of the rocks or banks between which the water flows,
should be noted, and the relations between cause and effect
elicited by questioning. The hardness of the rocks at 4
has prevented the channel from being widened to a greater
extent by the water, and accounts for the rapidity of the
flow. A glass of water collected here is found to contain
much suspended gravel. The considerable loss of weight of
bodies in water is noteworthy, as explaining the great size of
the stones which may be transported by rivers. The scour-

THE SCHOOL JOURNEY 395

ing action of such stones is shown in the fine “ potholes
at 4 and below the waterfall (Fig. 238) at to, and has
resulted also in the quaint stone* portico of the “ Fairies’
Chapel ” ilnder the right (west) bank of the river at 7.

G A Close, photographer, Rochdale.

Fig. 238. — Waterfall, Healey Dell, Rochdale (marked “ lo" in 237),

Again, the difference in the rates of erosion of hard and soft
rocks has had much to do with forming the waterfalls at 5
and 10. Where the stream is. wider and the flow slower
(as at 6 and 9, and below 10), may be noticed sand and
mud deposits; and where the stream makes a bend it is

396 AN INTRODUCTION TO NATURE-STUDY

found that the slowest flow and the maxjn\um deposit are
on the convex bank ; while the concave bank is worn
almost vertical (as at 6* and other places) by the swifter
rush of the water, and may be undercut to sucfi an extent
as to cause the bank to give way. In this manner a river
is constantly changing its course. 'Fhe weir at 13, and the
old water wheel still to be seen in the ruined mill below,
suggest remarks on the' motive ])ower of water, and on the
circumstances which may cause the old industries of a
nlf . tried to be su[)erseded by new ones. Along the rest of
the route the bed of the river is less steep and its banks
exhibit less variation, but they still afford plenty of mate^rial
for study. 'The railway viaduct at 14 and an aciueduct at 16
suggest at least a casual r^ferencti to the derivation of the
terms. Before the pupils are askeal to write a “composi-
tion ” on the ramhlb, a revision lesson on the features-
noticed should be given, and thev accuracy of the entries
on the sketch-maps checked by com{)arison with an en-
larged nui]) drawn by the teacher, or with a large “parish
plan ’ of the Ordnance Survey, on the scale of 25.3 inches
to the mile.

It will be well to devote two or more journeys to the
study of the trees along the route. One journey should
be taken in the spring, before the leaves are out, and,
another in the summer, when the foliage is well developed.
It is far better to study three kinds of trees in some detail
than to risk confusion at the beginning by attending to a
dozen. In Healey Dell the commonest trees are beech,
oak, and sycamore, and these serve admirably as an intro-
duction to tree lore. If the first tree-journey be taken in
the summcT, the leaves of some three abundant species
should be compared and contrasted, and each pupil should
secure good specimens, to be drawn and preserved after-
wards. The presence of a little bud in the “ axil ” (the

THE SCHOOL JO^JRNEY 397

upper angle between leaf and twig) of most of the leaves
should be pointed out by the teacher ; and since the
arrangement of the buds (and therefore of the subsequent
branches of the twig) thus depends* on the j)ositions of the
leaves, this last point is of considerable interest. In the
sycamore, tlie leaves are in pairs at rfght angles to each
other ; in the beech and oak they are single and alternate,
but much more crowded together in the oak than in the
beech. •The bark of the three trees is eq-ally distinctive,
and with the method of branching (obscured when
foliage is thick) serves to identify the trees from a distance
in the* winter. In winter and spring the inteiest of a tree
is centred in its buds, and there are few things which more,
richly repay study. In springy atlentic'm should also be
given to the flowers — generally arranged in catkins— -of
.common tret^. Separate sketch-majis should be used as
records of the positions of the more notable trees or
plantations along the route. Any <ienden('y to vandalism
on the part of the pupils by tearing off branches should,
of course, be sternly repressed ; especially interesting twigs
should, on occasion, be cut off by the teacher only, for
later study.

There is much divt;rsity of opinion as to the way in
.which flowers may be best studied in a limited number of
school journeys. In most ca^ses it will {)(Thaf)s be im
j)racticable to attempt more than teaching the names and
calling atlentiott to the habitat of the commonest. This,
though a necessary introduction to the subject, tends to
degenerate into a mere exercise of the memory, and in
itself possesses little educational value. It should b(*
su{)plemented by a detailed examination of a typical flower
— say a buttercup — and by the explanation of the work of
each part. ‘ Once the pupW has understood that the single
duty of a flower is the production of healthy seeds, and has

398 AN|[NTRODUCllON TO NATURE-STUDY.

been led to notice how, by the aid of ingenious devices,
the up-to-date plants have learnt to call in the aid of
insects, while the more .conservative families still rely on
the aid of the wind, he' will be eager to discov^^r for him-
self “ how the ' thing works.” With young children it is
folly to attempt ary but the very broadest principles of
classification of flowers ; but quite young children can
appreciate the advance from flowers without petals, through
flowers with separate petals, to those with petals finited to
fqjni a tube (thus restricting the nectar more and more to
“ useful ” insects) ; and so understand the advantage which
a primrose has over a buttercup, and a buttercup dver^an
oak flower.

At least one journey shc^ld be given, in the autumn, to
the study of the dispersion of fruits and seeds. The pupils
should provide themselves with empty match-^oxes or chip,
pill-boxes. In this ramble the class may with advantage
be divided into four grpups. Group A will collect examples
of fruits and seeds which are dispersed by the wind ;
Group B, of fruits which by means of hooks or otherwise
become attached to the hides of grazing animals, and are
carried flir from the place where they grow ; Group C will
collect fruits which tempt animals to eat them for the sake
of sweet ])ulp (in these cases the pupils, should find out,
(a) how the fruit is made conspicuous, (^) how the seeds
themselves are protected from being injured by the
animals) ; while Group I) will search for specimens of
plants which sow their own seeds.

There still remains abundant material for study in this
walk, and mention only can be made of the sticklebacks,
frog-spawn, snails, caddis-worms, dragon -fly larvae, blood-
worms — of the ‘things creeping innumerable, both small
and great beasts ” — which have been found in' the river,
ponds, and wells along our route, and have been used to

THE SCHOOL JOlJRNEY

399

Stock the aquarium ; of llie rabbits and birds ; of the nests
of ants and wild bees and wasps; of a certain blackberry
bush (31) rich in interesting leaves ; and of a thousand
and one (;ther things which, under the guidance of a
judicious leader, may well be the means of teaching
children to see what they look at a’ad to think about
what they see. For this is the first and last object of
the school journey.

MONTHLY NATURE CALENDAR.'

JANUARY.

PLANT LIFL.

General. — As in December (p. 422).

Plants usually in flower. — Shepherd’s purse, daisy, snow-
drop, and a few othei^.

ANIMAL LIFE.

General. — As in December (p. ^ 22 ).

Mammals. — Bats (p. 255) reappear at the end of the month.
Birds. — Missel thrush (p. 306) sings.

Insects. — Winter pupae of butterflies and moths (Chap.
XIX.) may be found.

^ No attempt has been made to compile a complete calendar, the
events noticed being those only which are considered in this book.

MONTHLY NATURE CALENDAR

401

N.S.

402

AN introduction TO NATURE-STUDV

FEBRUARY.

PLANT LIFE.

General. — As in December.

Plants usually in flower. — Shepherd’s purse, daisy, snow-
drop, hazel, and a few others.

^Hedges are now clipped ; study the effect which this
treatment has upon subsequent growth.

Corn. — Barley and oats are sown.

Liverworts. — Spore cases of Pellia (p. 200) become visible.

ANIMAL LIFE.

General. — As in December.

Mammals. — Bats re£y;)pear.

Birds. — Thrushes and blackbirds pair and begin to build ;
study differences in song (pp. 304 and 308). Rooks repair
and build nests (p. 318).

Frogs (p. 332) reappear.

Insects. — Pupae of cabbage- white butterflies and other
Lepidoptera may t>e found. , ^

MONTHLY NATURE* CALENDAR

403

404

AN INTRODUCTION TO NATURE-STUDY

INARCH.

^ PLANT LIFE.

General Work for Spring Months. — Study the germination
of seeds and the early stages of growth of the new plants
(Chap. L); the structure and methods of unfolding ©f buds
IV. and VllL); the movements of young twining
stems; “bleeding” of stems, and paths of food-currents
(Chap. V.) ; and examine and collect spring flowers (("hap^.
VL, VIL, and VII L).

Plants usually in flower — Shepherd’s purse, marsh marigold,
wilfl plum, daisy, dandelion, daffodil, snowdrop, hazel, alder,
willow, poplar, elm, and others.

Horsetail. — Fertile haulms (p. i95)p.ppear.

Corn, — Barley and oatcrsowing continued.

ANIMAL LIFE.

General Work for Spring Months. — Study the develop-
ment of frogs and toads (Chap. XVIII.) and insects (Chap.
XIX.); the development and education of the chick (Chap.
XVL); the nesting-habits of birds (Chap XVII ); the educa-
tion and play of lambs and other young mammals (Chap.
XIV.); the habits of molluscs (Chap XX.); and the work of
earthworms (Chap. XX.). Stock aquaria.

Mammals. — Lambs are born. ^

Birds. — Thrushes, blackbirds, skylarks, rooks, and other
birds lay eggs. Fieldfares and redwings begin to depart.

Frogs and Toads lay their eggs.

Insects. — Dytiscus (p. 361) lays eggs. Pupae of cabbage-
white butterflies and other Lepidoptera may be found.

MONTHLY NATURE CALENDAR

406 AN INTRODUCTION TO NATURE-STUDY

.APEIK

, PLANT LIFE.

Hants usually in flower. — Wallflower, shepherd's purse,
buttercup), anemone, marsh marigold, common vetch, plum,
pear, strawberry, primrose, cowslip, daisy, dandelion,^ speed-
well^ red deadnettle, daffodil, wild hyacinth, wild tulip,
rushes, arum, annual meadow grass, oak, birch, alder, willow,
poplar, elm, ash, and others. *■

Trees which unfold their leaf-buds. — Larch, horse chestnut,
beech, elm, sycamore.

Elm fruits (p. 1 54) are abundant ; study the method of
dispersal (p. 173). ♦

Com. — Barley and oat sowing continued.

ANIMAL LIFE.

Birds. — Sand-martins, cuckoos, swallows, house-martins,
nightingales, swifts, and other birds arrive. Kestrels and
sparrow-hawks nest. Fieldfares and redwings depart.

Fro^ and Toads. — Tadpoles hatch. f

Insects. — Cahbage-white butterflies (p. 362) and other
Lepidoptera emerge from pupae. Caterpillars are plentiful.
Moths may be taken on willow flowers at beginning of month.
Larvae of Dytiscus (p. 361) and other aquatic insects
4 may be found in ponds

Molluscs. — Garden snails (p. 379) reappear.

MONTHLY NATURE CALENDAR

4 o8 an introduction TO NATURE-STUDY*

MAY.

PLANT LIFE.

Plants usually in flower. — Wallflower, shepherd’s purse,
buttercup, anemone, marsh marigold, laburnum, common
vetch, red clover, white clover, broom, cherry, apple, pear,
strawberry, hawthorn, primrose, cowslip, daisy, dandelion,
speedwell, red deadnettle, white deadnettle, lily of the
valley, wild hyacinth, star of Bethlehem, wild tulip, Aishcs,
sedges, arum, sweet-scented vernal grass, slender foxtail,
meadow foxtail, annual mej^dow grass, perennial rye grass,
oak, beech, birch, willow, elm, horse-chestnut, ash, sycamore,
and others. ,

Most forest trees are now in leaf.

Liverworts — Spore-ca,ses of Fellia (p. 200) open.

ANIMAL LIFE.

Birds. — Swallows build nests. Most birds are incubating
eggs (Chap. XVI)

Frogs and Toads. — Tadpoles may be foun^ in ponds.

Insects. — Moths and butterflies are common. Cabbage-
whites lay eggs. Caiterpillars of tiger-moth (p. 364) and other
Lepidoptera may he found. Aquatic insect-larvae in ponds.

MONTHLY NATURE CALENDAR

409

410

AN INTRODUCTION TO NATURE-STUDV

JUNE.

PLANT LIFE.

General Work for Summer Months. — Study the forms
and duties of leaves (Chap. III.); and the thickening of
stems (Chap. V.). Examine, identify, and colie A grasses
(Chap. VIL) and summer flowers (Chap. VI.), and make
observations upon cross-pollination of flowers by insects
(Chap. VL). Study the development and Structure of frhits
(Chap. IX.); and the life-history of ferns (Chap. X.). Com-
pare and contrast niushrooins and toadstools (Chap. XL).

Plants usually in flower. — Wallflower, shepherd's purse,
buttercup, anemone, tneadow vetchling, common vetch, red*
clover, white clover, broom, wild r rose, hawthorn, poison
hemlock, cow parsnip, carrot, daisy, dandelion, speedwell,
mullein, snapdragon, thyme, sage* red deadhettle, white dead-
nettle, lily of the valley, wild hyacinth, star of Bethlehaai,
rushes, sedges, sweet-scented vernal grass, slender foxtail,
meadow foxtail, Timothy grass, Yorkshire fog, wild oat, annual
meadow grass, smooth-stalked meadow grass, rough-stalked
meadow grass, meadow fescue, sheep’s* fescue, perennial
rye grass, couch grass, lime, sycamore, and others.

Lime leaves unfold

Fruits of strawberry, willow, and other, plants care ripe.

Haymaking begins.

ANIMAL LIFE.

Mammals, — Examinfe young wild rabbits (Chap. XIL).
Birds. — Most birds are hatching eggs. First brood of

MONTHLY NATURE CALENDAR

411

swallows batched at end of month. Drake’s plumage be-
comes similar to duck’s (p. 329).

Frogs and ^oads. — Tadpoles reach full size.

Insects. — All stages of Lepidoptera very abundant. Cater-
pillars of tiger-moth (p 364) pupate at end of month.
Vapourer caterpillars (p. 364) may be found at end of
month. Larvae of aquatic insects in ponds ; pupae of
Dytiscus 361) in soil on banks.

412

AN INTRODUCTION TO NATU KE-STUI>Y

JULY.

PLANl^ LIFE.

Plants in flower. — Shepherd’s purse, candytuft, buttercup,
meadow vetchling, red clover, white clover, wild rose, black-
berry, poison hemlock, water hemlock, cow parsfiip, carrot,
Ijedge parsley, fool’s parsley, water dropwort, daisy, dande-
lion, thistle, foxglove, speedwell, snapdragon, mullein, musk,
mint, thyme, sage, red deadnettle," white deadnettl6, nsshes,
slender foxtail, Timothy grass, Yorkshire fog, wild oat,
annual meadow grass, sny^oth-stalked meadow grass, rough-
stalked meadow grass, meadow fescue, sheep's fescue, couch
grass, Spanish chestnut, lime, and others. ^

Fruits of gooseberry, cherry, Raspberry, strawberry, and
other plants are ripci

Ferns, — Spores of male-fern,^ bracken*, and hart’s tongue
are ripe (Chap. X.).

Fungi. — Mushrooms (p. 203) and toadstools may be found.

ANIMAL LIFE.

Mammals. — Lambs are weaned.

Birds. — Many birds are hatching second broods. Old
cuckoos begin to depart at end of month. Poultry moult.
Young wild ducks may be seen in water meadows.

Frogs and Toads. — Young animals leave ponds.

Insects. — Cabbage-white caterpillars pupate. Tiger moths
(p. 369) emerge from pupae at end of month. Caterpillars
of vapourer moth (p. 364) may be found.

MONTHLY NATURE cAlENDAR

413

414 an INTRODI/CTION TO NATURE-STUaY

. AUGUST.

( (

PLANT LIFE.

Plants in flower.-!— Shepherd’s purse, candytuft, buttercup,
meadow vetchling, red clover, white clover, wild rose, black-
berry, water hemlock, cow parsnip, carrot, hedge parsley,
fool’s parsley, water dropWort, daisy, dandelion, thistle, fox-
gif've, speedwell, snapdragon, mullein, musk, mint, thyme,
sage, red deadnettle, white deadnettle, rushes, slender fox-
tail, Timothy grass, Yorkshire fog, wild oat, annual meadow
grass, couch grass, and others.

Leaves of horse chestnut^begin^ to fall.

Fruits of cherry, plum, raspberry, and oth^ plants are ripe.

Corn. — Wheat, oats, and barley harvests begin. '■

Ferns. — Spores of male-fern, t^facken, and hart’s tongue
are ripe. *

Fungi. — Mushrooms and toadkools may be found.
ANIMAL LIFE.

Birds. — Swifts and old cuckoos depart. Many rooks ^o
into winter quarters. Nightingales begin to depart. Sand-
martins congregate. Song-birds are comparatively silent.

Insects. — All stages of vapourer moth may be found.

MONTHLY NATURE tALENDAR

4i6 an introduction TO NATURE-STUDY

SEPTEMBER.

PLANT LIFE.

General Work for Autumn Months. — Study the storage
of food in twigs, underground stems, bullis, etc. (Chaps. IV.
and V.); collect good specimens of leaves showing autumn
colours, observe the phenomena of leaf-fail and the formation
of vegetable mould, and notice the order in which forest
trees become leafless (Chaps. IV. and VIII.). Sttidyt^the
development and structure of fruits, and the methods of dis-
persal of seeds (Chap. IX. Make collections of dry fruits
((.fliap. IX.), and of the “seeds” of useful and injurious,
grasses (Chap. VII.).*, ^

Plants usually in flower.— Sheph^ercFs purse, buttercup,
meadow vetchling, r/xl clover, fvhite clover, blackberry,
hedge parsley, water dropwortj daisy, dandelion, thistle,
foxglove, speedwell, snapdragon, musk, mint, red deadnettle,
white deadnettle, slender foxtail, annual meadow grass, and
others.

Ash and horse chestnut leaves fall.

Fruits of apple, pear, plum, blackberryf and other plants
are ripe.

Corn.- Wheat-sowing begins.

Fungi.— Mushrooms and toadstools may be found.

ANIMAL LIFE.

General Work for Autumn Months. — Study the various
methods by which animals prepare for the winter : e.g.
migration of birds, hibernation of bats, frogs, insects, etc.;
change of colour or thickness of coat, storage of food, etc.

MONTIIl.Y NATURE CALENDAR

417

Birds. — SwalloM\s and house-martins congregate. Sand-
martins and nightingales depart. Rooks go into winter
quarters. Young song-birds may be heard learning to sing.

Insects. — Moths may be taken on ivy blossoms, etc. Eggs
of cabbage-white butterflies may be found. Caterpillars are
mostly full fed and ready to {)iipate. Ihjpae of vapourer
moth may be found.

N.S.

4i8 an introduction TO NATURE STUDV

OCTOBER.

PLANT LIFE.

Plants usually in flower. — Shepherd’s purse, white clover,
daisy, dandelion, snapdragon, red deadnettle, white dead-
nettle, slender foxtail, and others.

«Alost forest-trees shed their leaves.

Fruits of apple, pear, plum, and other plants are ripe.

Com. — Wheat-sowing continued.

ANIMAL* LIFE.

Birds. — Young sori^-birds may be heard learning to singi.
Fieldfares and redwings arrive. Sr/allows and house-martins,
depart. Drakes reasfume their distinctive plumage.

Frogs hibernate (p 334). 1

Insects. — October is the best month for pupa hunting.

MONTHLY NATURE tALENDAR

419

N.S.

2 D 2

420 AN INTRODUd'ION TO NATURE-STUDY*

NOVEMBEB.

PLANT LIFE.

Plants usually in flower. — Shepherd’s purse, daisy, white
deadnettle, and others.

Most forest-trees are now leafless.

Fruits of hawthorn, rose, holly, mistletoe, etc., are ripe.
Com. — Wheat-sowing continued.

ANIMAL LIFE.

Mammals. —Bats hibernate (p. i'57)»

Birds. — Larks patrol fields in flocks (p. 3181^

Insects. — Pupae may be found

MONTHLY NATURE CALENDAR

422

AN INTRODUCTION TO NATURE-STUDY

DECEMBER.

, PLANT LIFE.

General Work for Winter Months. — Arrange collections
of flowers, grasses, leaves, etc. Study the methods of
branching, and the bark, of trees, and make drawTngs of
typio<=»-’ examples (Chap. VIII.). Examine bulbs and corms,
(("hap. V.) and grow them in water-glasses. Trace the
water-conducting strands in the flower-stalks of snowdrop,
narcissus, etc. (Chap. V.)

Flowers of daisy, white dea^netUe, and a few others may
be found.

Fruits of mistletoe, holly, etc., are ripe.

ANIMAL LIFE.

General Work for Winter Months. — Prepare skeletons,
etc., and study the structure and manner of life of rabbits,
poultry, and pigeons (Chaps. XIL, XIIL, and XV.). In
snowy weather, examine and draw the footprints of domestic
and other animals (Chap. XIV.). Place gr^in, crumbs, suet,
and other food for birds, and identify those which come to
feed (Chap. XVII.).

Birds. — Missel-thrush sings. Sparrow-hawks may be seen
near farms.

Insects. — Pupae may be found.

MONTHLY NATURE CALENDAR 421

TYPICAL EXAMINATION PAPERS.

The National Froebel Union.

ELEMENTARY CERTIFICATE. Nature Knowledge.—
Paper I.

{Questions i and 2 and any two others to be answered.'^

1. Describe the flower provided, and draw it in longitudinal section.

Explain how crosS' pollination is ensured in this flower ; give drawings
to illustrate. " * ^

2. Give and plan out the subject-matter for one or more Lessons, to

be given to children of seven or ci^ht years of age, on the Dispersal of
PTuits and Seeds by Animals. *

3. Describe the structure^ of an Acorn and of a Wheat grain, and
contrast these two seeds. Give enlarged drawings of each.

4. What is the work of the root of a pkant, and how is this work
carried out? What differenf* forms of root^ are to^be found? Give
examples and make a rough sketch of eacMt

5. Describe the bud in winter, and its method of unfolding in spring,
of any two of the following trees : — Oak, Beech, Sycamore. Make
sketches to illustrate.

6. Make as complete a list as you can of Flowering Plants which
grow in ponds ; state how these plants have adapted themselves to their
habitat, ^nd say at what time of the year each of them flowers. What
plants would you expect to find growing round the margin of the pond?

Paper II.

{Questions i and 2 must be answered^ and any three others,)

1. Draw up Notes of Lessons on one of the following subjects : — “ A
Mole,” “Domestic Fowls,” “A Cat.” State the age of the children,
and the method you would pursue.

2. What is a ruminantl Give as many groups of ruminatirijg animals

as you can and the habits of one, ^

TYPICAL EXAMINATJON PAPERS

425

3. Give the life-history oi^otte of the following, wilh illustrations
a Bee, a Caddis-fly, a Spider, a Butterfly.

4. Give the life and habits of the Squirrel.

5. How (ioes a Starling differ from othar Birds ?

6. Draw a common Snail and a Slug. Give a short account of their
life-histories.

7. Give instances of protective colowing amongst (i) Insects, (2)
Birds, (3) Mammals, in this country.

Board of Education.

TEACHERS’ CERJIFKi^TE EXAMINATION.

General Elementary ^Science.

Part II.

11. Give an example in each case of a gjant with — (a) IMurned fruits
or seeds, [b) Winged fruits seeds, (r) Climbing stem covered with
hooks, {d) Flowers which come out before the leases. (^) Flowers in
which the stamens are united to form a tube.

12. Show in the case of any two British wild plants the special means
they possess for survival in the struggle for existence.

13. Name five of the earliest flowering wild plants in your neighbour-

hood, in the order in which they flower, and mention the chief
characteristics of the flower in each case. '

14. Describe the life-history of a fern so far as it can be observed by
the naked eytt and with the aid of a pocket lens.

15. Describe, with the help of drawings, the work of a bee in its
mode both of collecting pollen and honey and of fertilising flow^ers.

16. Give a short account of the structure of a bird’s wing. How are
the wings made use' of during flight ?

17. Giv^ an account of some simple experiments you w^ould employ
to demonstrate the phenomena of respiration in animals and plants.

426 AN INTRODUCJION TO NATURE-STUDY ■

Board of Education.

PRELIMINARY EX-^MINATION FOR THE CERTIFICATE.

Part II.

Ei.kmentarv Sr fence.— Syllabus No. II.

^ ( You should answer six questions. )

1. l)esciril)e with the aid of a diawing the various structvires seen ]^)y
means of a pocket lens in a section across the middle region of a giain
of wheat.

2. How would you measure th^rale qf transpiration of water from a
small plant or a leafy stem ?

3. How can it he shovvn*that the root responds to external influences
of moisture, light and gravity ?

4. Give a brief account^of the function of tlie green leaf in the

nutrition of plants. ^ •

5. Compare by drawings the leaves of broad bean and garden pea.
Then discuss the means by which the two plants obtain mechanical
support.

6. When the bulb of a thermometer is placed in a jar of soaked and
germinating seeds, what temperature change is observed? Explain the
cause of this.

7. Describe experiments which show in what respects the air is
affected in composition by passing through the lungs.

8. Describe with the help of drawings the structure of^he flowers of
the hazel or willow and show how they are adapted for cross-pollination.

9. What is meant by root pressure, and how would you demonstrate
it ? Illustrate your answer by drawings.

10. What are the conditions of the soil which make it a suitable
medium for healthy root’action and vigorous plant growth ? .Conversely
under what conditions of soil would the plant fiiil to thrive or die?

TYPICAL EXAMINAION PAPERS

427

Board of Education (Squth Kensington).

General Biology.

Section I. of Stage I.

( You are permitted to answer onlv Ew;irr i] nest ions.)

1. Write what you can of the habits of llic common House Fly and of
the cor^mon Clothe.s Moth ; draw figures of their appearance at
different stages of tlie life- history.

2. Where and when do you find Frog’s eggs? Of wliat iib?r*is the
jelly \^th which they are surrounded ?

3. How does the Tadpole swim, and how does the Frog swim?
fjj^ow does the Frog jump, and how does it catch a fly ?

4. Contrast the characters ^ the #iouth (including teeth if present) in
the Frog, Bird, Cat, Kahhit and Sheep.

5. ‘'Describe ttie characteristic modes of locomotion in the P>ird, Dc^g,
Rabbit and Bat, and poin4 out any peculiarities of the skeleton which
are related to these habits. '•

6. Describe the heart of th^ Sheep, and account so far as you can for
any differences you can point out between the various chambeis.

7. Tn what way are bees useful to flowers? Explain in* any one
example you choose what happens when a bee visits the flower.

8. Describe the roots of a pea or bean. What importance do you
attach to the different parts you mention ?

9. What is starch? How would you show whether or not it was
present in a leaf? What conditions are necessary in order that the leaf
may produce it ?

10. Describe the fruit of either the Sycamoie or the Poppy, and
explain the uses of the different parts in dispersing the seed.

11. Describe how you would proceed in arranging an experiment to
enable you to study the germination of a seed. Give a brief account of
the process of germination of any seed you may select.

12. Describe and sketch the specimen provided, and explain, as far
as you can, the use of the different parts.

Air, carbon dioxide in, 31, 33
Air-chamber of hen’s egg,
283, 285

Air sacs of birds, 279
Albumin, 285
Alder, 142, 149
Allantois, 289, 293
Alternation of generations,
189, 196

Amnion, 288, 290
Anemone, 97, 98
Animals and plants, resem-
blances and differences, 243
Annual, meadow grass, 135 ;

rings, 73
Anterior, 217
Anther of stamen, qi
Aorta, 236, 238
Appendages 4of crayfish and
lobster, 373, 375
Apple, 104, 106 ; fruit of, 176,
179

Apricot, 106

Aquarium, a simple, 340
Arachnids, 378
Arteries, 237, 238
Arteries, pulse m, 235, 239
Arthropods, 351
Arum, 122

Ash, 153, 156 ; fruit of, 171,
173; mountain, 157
Aspen, 152

Auricles of heart, 235, 237
Awn, 129, 130, 131
Axil of leaf, 45, 47

Backbone, of pigeon, 269;

of rabbit, 217, 222, 227
Bacteria, 209

Balancers of hen’s egg, 283,
2B5

Bark, 74
Bast, 71, 72

INDEX.

Bat, 25s, 256

Bean seed, i, 2, 5 ; germina-
tion of, 9, 13 ; starch in, 2
Beech, 142, 145, 147 ; fruit of,
’ 75 , 178

Beetle, a water, 357
Beetle.s, 362 »

Berries, I75fi79 «

Biennials, 31, 96
Bile, 232, 234
Bir4afi.z42, 147, 148
Birds, 269

Bird’s foot trefoil, 102 g
Black bent, 135 _

BlacJ[berry, 103, 105 ; fruit of,
175, 179; leaves, 38, 41,
105 . 4

Blackbird, 302, 307
Bleeding of stems, 67, 70
Blood, 233, 235, 242* ; circula-
tion of, 23s ; red corpuscles
of, 237, 242
Blue mould, 207, 208
Bone, structure of a long, 223,
228

Bonti^ of birds, 269 ; of pigeon,
274 ; of rabbit, 222
Box leaves, 44, 45
Bracken fern, 184, 189
Bracts of anemone, 97, 99 ; of
daisy, ni ; of dandelion,
up ; of lime, 152, 154, 155,
^^74

Branches, position of, 45, 47
Breast bone, of pigeon, 269 ;

of rabbit, 217, 223, 227
Breathing, definition of, 242 ;
nece.ssity for, 241 ; of cock-
roach, 355 ; of crustaceans,
376, 377 ; of fresh- water
mussel, 381 ; of frog, 333,
337 ; of mammals, 242, 243 ;
of snails, 382, 383; of tad-
pole, 344

Breathing organ of chick -
embryo, 289, 294
Broad bearl seeck, i, 2^5
Broccoli, 96
Broom, loi
Brussels sprouts, 96,

Bud, a typical, 55, §8*

Buds, 55, 69 ; bursting of, 56,
61, 64 ; of ash, 153, 156 of
horse chestnut, 57, 63 ; of
sylkmore, 56, #>; position
of, 45, 50
Bulb, 81, 84

Burrows of earthworms, 3^4,

385

Buttercup, 96, 97 ; family, 96,

* 97

Butterflies, cabbage - white,
362, 365 ^

Calamites, 196
Calceolaria, 116
Calyx, 90
Cambium, 72
Candytuft, 94
Canine teeth, 246, 248, 255^,
Capillaries, 237, 240
Capsule, 168

Carbon, contained in plants,
3I1 33 » contained in starch,
32

Carbon^ dioxide, formed by
living body, 240, 241 ;

formed when flesn burns,
240, 241 ; formed when wood
burns, 31 ; in air, 31, 33
Carnivores, 254
Carpel, 96, 98
Carrot, 96, to8
Castings of earthworms, 384,

386

Cat, 246, 350, 252, 254
Catkin, 146

Catkins, of alder, 14a, 149 ; of

'INDEX

429

beech, 142, 148 ; of birch,
142, XifS ; of hazel, 242, 149 ;
of oak, 141, i44j 14S*; of
poplar, 1 51 ; of willow, 15^,
151 ' ,

Caterpillar, of cabbage- whiter
butterfly, 362, sbji; of flger-
moth, 364, 369 ; of vapourer-
. moth, 364, 370 „
CauUflower, 96 *

Celery, 108
Centipedes, 378
Cephalothorax of crab, 373,
376 ; of crayfish and lobster,

372,375 ^ ^ .

Cherry, 103, 1^, 106 ; fruit

of, 17s, 79

Chestnut, horse, 38, 42, 47,
57 , 63, 65, 157, 159 ; Spanish
or sweet, 148

Chick, development of, 286,
289 ;<leduc^ion of, 295, 296 ;
embryo of, 287, 289 ; hatch-
ing of, 294, 295
Chitm,^5i
Chrysalis, 366
Claws of cat, 247, 251
Cleavers, 175, 177
Climbing stems, 75 ^

Cl,k*ellum df earthworm, 383,
286

“Clock” of dandelion, 112,
171, 172

Clover, loi, 102
Cockroach, 240, 351 ; habits
of, 3§6*Ufe history of, 256 ;
position of in insect class,

• 357 ; structure of, 355
Cocoon of earthworm, 386 ; of

tiger-moth, 364, 3^9
I Coleoptera, 362
Collar of mushroom, 203, 205 ;

of garden snail, 379
Collecting, 389, 390
Colbur, of flowers, 93 ; cf
(.fruits, 182
Compositae, 114
Cone-bearing trees, 160, 161
Cones of alderf 149 ; of horse-
tail, 191, 192, 194, IQS ; of
larch, i6i, 163; oifc Scotch
pine, r6o, 162, 171, 1.74 ; of
spruce fir, 163, 171, 174
Convolvulus, 76, 78, 79
Cork, 75
Corm, 81, 85
Corolla, 91
Corona, 120, 122
Cotyledons, 13, 16, 22, 23 ; of

# bean, 2, 6
Cowslip, 109, 1 10
Crayfish, 372, 374

Creeping stems, 80, 82
Cress, f)4, 96
Crocus corm, 81, 85
Crop of pigeon, 271
Cross .fertilisation, ,92, 102,
ltd; 118, 122, isr
Crow, 312, 318, 32o;%‘amily,
312, 320
Crucifers, 95
Crustaceans, 372, 377
Cuckoo, 322, 324 ; cuckoo-
pint, 122

Currants, 176, 179
Cushion-feet of caterpillar, 365

DaFFOPIL, 84, 85, 120, 122
Daisy, rii, 112
Dandelion, n2, 113; fruit of,
171, 172
Deadnettle, it7
Deer, 261
Dentine, 219

Development of chick, 286,
289 ; of frog, 340
Diaphragm, 218
Diastase, 234 %

Dicotyleflbns, 23, 40, 72
Digestion, 231, 233 ; defini-
tion of, 233 ^

Digestive canal of frog, 231 ;

of rabbit, 232
Dipt»a, 370 ^

Disperlbl of insects, 370 ; of
seeds, 165 •

Dissection, 214
Dog, 248^251, 252, 254
Donkey, 261
Dorsal, 217

Down featners, 273, 277
Diopwort, water, 108
Duck, 326, 327

Dytlscus, habits and structure
of, 357, 358 ; life history of,
361

Ear, of grass, 130
Ears, of rabbit, 218
Earthworms, 383, 384
Education of young animals,
248, 249, 262

Eggs, of cabbage- white butter-
fly, 362 ; of cockroach, 357 ;
of Dytiscus, 361 ; of earth-
worm, 386; of frog, 339,

‘ 340, 341 ; of hen, 282, 284 ;

of Limnaea, 380
Elm, 152, 153 ; fruit of, 171,
*73

Embryo, 12; of chick, 287,
289 ; of fern, 188, 191 ; of
horsetail, 195
Enamel, 219

Endosperm, aa
Evolution, a care of, 338
Extinct horsetails, i0
Eyes, of butterfly, 363, 367,
368; of cat, 246, 250; of
cockroach, 348, 352 ; of crab.
373 ; of crayfish and lobster,
372 ; of dog, 248, 251 ; of
pigeon, 271 ; of rabbit, 218 ;
of snail, 379, 382

Falcon, 272, 330
Fantail pigeon, 280
Feathers of pigeon, 265, 266,

^ 267, 270, 275, 276
Feelers, of butterfly, 363, 367 ;
of cockroach, 349, 352 ; of
crayfish and lobster, 372,
373. 374. 375 : r^^Dytiscus,
388 , 359 ; of moth, 364, 368,

36Q

Fehling’s solution, 230
Ferns, 183 ; bracken, 184,
189 ; hart’s tongue, 185, 190,
191 ; male fern, 183, 185
Fertilisation, 92 ; of ferns,
188 ; of forest trees, 146 ; of
foxglove, 116; of grasses,
131 ; of horsetail, 195 ; of
moss, 202 ; of oak, 14s ; of
primrose, 109 ; of red clover,
lot ; of Scotch pine, 162
Fescues, 132, 134.

Fieldfare, 303, 309
Field work, 388
Filament of stamen, 91
Fir, spruce, r6i, 163
Flight of bird, 278
B'lower. of a grass, 128, 129;

of wallflower, 88, 89
Flowerless plants, 197
Flowers, work of, 89
Food, carbonaceous, of plants,
34, 35 ; mineral, of plants,

' 29 ; necessity of, 230 ; ob-
tained from air, 31, 34.
obtained from soil, 26, 29;
of mushroom, 204, 206 ; cA
young seedling, 28
Fool’s parsley, 108
fowls, 296, 29Q
Foxglove, 114, 1x5*, family.
1 * 4 .. 1*5

Foxtails, 132, 134, 135
Frog, development of, 340 ;
digestive canal of, 231 ; life
of, 33 ^. 334

Fronds of ferns, 65, 183, 184,
x86, 180
Fruit, 166

Fruit, of apple, 176, 179 ; of
ash, 171, 173 ; of beech, 175,

430

AN INTRODUCTION TO NATURE-STUDY '

178 ; of blackberry, 175, [

179 ; of Imttercup, 98 ; of '
cherry, 175, 179; of dande- |
lion, X71, 172 ; of elm, 171, [
173 ; of field geranium, 165, '
168 ; of gooseberry, 175,
179; of lia/el, 175, 177 ; of
herb bennet, 174, 177 ; of
lime, 174 ; of oak, 175, 177 ;
of pansy, 166, 169 ; of pea,

7, 165, j68 ; of pear, 176,
180 ; of penny-cress, 165,
i 63 ; of plum, 175, t79 ; of
poppy 166, 168 ; of rasp-
berry, 175, 179 ; of rose,
176, t8o; of shepherd’s purse,
16s ; of strawberry, 17O, jBo,
181; of sycamoie, 3, 171
J73; of#>.getable marrow,
170, 179 ; of violet, j 66,
169 ; of wallflower, 165,
167 ; of willow, 171, 173; of
wocxl aveiis, 174, 177

Fruits, colour of, 182 ; hooked,
I 74 -.I 77

Kunai ia, 199, 202
Fungi, 206, 244
Fur, of bat, 25b ; of cat, 246,
250 ; of rabbit, 212, 216

Gali.s, 141, 146
Gastric juice. 232, 233
Geranium, fruit of, 165, t68
Germinal disc, 285, 287, 289
Germination, 12. 21
Gills, of crab, 374 ; of crayfish
and lobster, 373, 376; of
fresh-water mussel, 379, 381 ;
of mushroom, 203, 205 ; of
tadpole, 341, 344, 346
Gizzard of pigeon, 271
Gloxinia, 116
Glumes, 129, 130
Goats, 2b I

Gooseberry, 175, 179
Goose grass, 175, 177
Gorse, 10 1
Grapes, 176, 179
Grasses, 125

Grass, flowers of, 128, 129 ;

reproduction of, 128
Grass stems, 72, 75
Grinding teeth of rabbit, 219
Gullet, 231, 232
Gymnosperms, 72, 163

Hair, of cat, 246, 250 ; of
dog, 248, 251 ; of sheep, 258
Han’s tongue fern, 185, 190,
19T

Hatching, of chick, 294, 295 ;
of tadpole, 340, 344

Haulms, of grasses, j2<5, 127 ;
of horsetail, 191, 193,

Ha'As, 329

Hawthoijii, 106

Hazel, 142, 149 ; fruit 01, 175,

177 •

Head, of clover, loi, 102 ; of
daisy, 113; of dandelion, 113
Heart, beats of, 235, 239 ; of
, chick -embryo, 288, 291 ; of
cockroach, 350, 355, 356 ;
sheep’s, structure of, 235,
237 ; valves of, 23b, 238, 239
Heimptera, 370
Hemlock, poison, 106, 107 ;
water, 108

Hen, eggs of, 282, 284
Herl>-beiinei, fruit of, 174, 177
Heredity, 217, 339
Hip bones of rabbit, 223, 228
Hip of rose, 176, 180
Honey-dew, 158
Honeysuckle, 78
Hoofed mammals, 257
Hoofs, 258, #59, 261
Hooked fruits, 174, *^77
Hooking stems, 75

1 HoiiflS, 2S7, 2SQ
I Horse, limbs of, 261
I Horse chestnut, 157, 159;

' buds of, 57, 63 ; ledges of,
38 42, 47, 64 •

Hor.#;tail, 191
House-martin, 311,-315
House-sparrows, 3:^, 320
Hovering, 279, 331
Hyacinth, 84, 119, 120
Hyinenoptera, 370
Hypha of mushroom, 205
Hyphae of moulds, 208, 209

Imac.o, 363

Incisor teeth of rabbit, 213,
219

Incubator, a simple, 286
Insect, definition of, 351
Insects, 349
Instinct, 252, 296
Internodes, 45
Intestines, 231, 232
Iodine solution, 2
Irritability, 116
Ivy, leaves, 38, 43 ; stem, 75,-
77 . 78

ACODIN PIGKON, 280
aws, of cockroach, 349, 352,
354 ; of crayfish, 375 J of
rabbit, 222, 226 ; of sheep,
857 . 259

Keel, of bird’s breast-bone,
274 ; of pea flower, 100, 102
Cesft-el, 320, 330
tCeys, of ash, 153, 156 ; of syca-
more, 159
Kittens, 248
•

Lahial palps, of cockro«ach,
353 ; of Lepidoptera, 367
Labiates, 117

Labium, of caterpillar, 363,
365 ; of cockroach, 349, 353
Labrum of cockroach, 349, 352
Laburnum, 101, 102
Lambs, 258, 262
r.aik, 31 1, 31^

Larva, of cabbage • white
butterfly, 362, 305 : of Dytis-
cus, 361 ; of tiger-moth, 364,
369 ; of vapourer-moth, 364,

Leaf fall, 55, 59* ^

Leaf of a grass, 127
Leave*-. nm-’peTe’-t c^, 44;
of '■!. ■ ’l’ c: \ . ■ I. 105 ;

of box. 44, 45 ; 01 leins, 65,
i8j, 184, 185, 186, 189, 191 ;
of horse chestnut, 38, 42, -47,
60; of ivy, 38, 43 ; of rose,
38, 42 ; of sweet pea, 39, '43;
of sycamore, 38, 42, 58, 157,
158 ; shapes of, 37, 40 :
simple and compound, 41 ;
skeleton, 37, 39; veins of,

• 37, 39 > work of, 48
Legume, 165, 108
Ligule, 125, 127
Lily family, 1T9, 120 •

l.imbs, movement of 225 ; of
cat, 246 ; of chick -embryo,
288, 292; of dog, 248; ofp,
pigeon, 266, 270', of r.ibbitj
216,223, 228 ; of sheep, 259.

261

|*Lime,J52, 154,155 ; fruit dl‘, 17^
Lirnnaga, 379, 382

Livery32, 233

Liver-Wrt, 199, 200
Lobster, 372,^74
Locomotion, of cat, 247, 251 ;
of c*ab, 377 ; of dog, 249,
251 ; of earthworm, 383,
385 ; of fresh-water mussel,
380 ; of garden snail, 379,
382; of insects, 353, 360,
368 ; of rabbit, 216
Lombardy poplar, 150, 152
“ Lords and Ladies,” 122

Lupine seed, 3, 7, ii, 14

Maize SEED, 18, 19 ; germina-
tion of, 21

INDEX

431

Male fern, 183, 185 ,

Mammals, 220

Mandibles, of caterpillar, 365 ;
of cockroach, 349, 352 ; of
crayfish and lobster, 373,

Mantle of fresh-water mussel,
378, 381 ; of i^arden snail, I
.. 379 . 381 . I

Maps, use of, in N ature-study, 1

Marjoram, ii8
Marsh marigold, 97, 98
Martin, house, 311, 315 ; sand,
Vh 315 •

Mast of beech, 142
Mastication, 219
Mavis, 30T, 303
Maxillae, of cockroach, 350,
353 *^of craf'fish and lobster,
373 . 375; Lepidoptera,
3^7

Maxillary palps of cockroach,

353 ^ ,

Maxillipedes of crayfish and
.lobster, 373, 375
Meadow, caistail, 132, 136;
fescue, 132, 134 ; flovUr of,
■131 ; foxtail, 132, 1^4, 135;

^ grasses, 132, 135 ; vetchling,

lOT

Medullary rays, 74
Metamorphosis of frog, 346
Mineial matter in plants, 56 ,
28, 29
*Mint, 118

Missel-thrush, 302, 306
Molluscs, 378
Monkshood, 99
Monocotyledons, 23, 40
Mosses, 199, 201
Moth, 368 ; tiger-moth, 364,
§369 ; vapourcr-rnoth, 3^,

. 369

Moulds, 207, 208 A
Moulting of bird^*a77, 327,

329

Mountain ash, 157
Mucor, 207, 208 ^

Mullein, 116

Muscles, action of, 224, 225
Mushroom, 203
Musk, 115, ri6
Mussel, fresh-water, 378, 380
Mustard, 94, 96: seed, 3, 7

Mycelium, of moulds, 208,
209; of mushroom, 203, 205
Myriapods, 378 • .

Narcissus, 120
Natural selection, 217, 338

Nectar^H go
Neurop^era, 370
Nodes, 45
Nuts, 175, 177

Oak, 140, 142 ; family, 140 ;

fruit of, 175, 177
Oat, 133, 136
Oranges, 176, 179
Orthopteia, 357
Ovary, 92
Ovule, 92
Oxen, 261

Oxygen, liberated by leaves,

48, 51

Pales, 129, 130
Pancreas, 232, 233
Pancreatic juice, 232, 234
Panicle, 130
Pansy, fruit of, 166, 169
Parsley, 108; family, 106,
107 ; i<4 ; hedge, 107

'^arsnip, 108

Passerine order of bir<is, 320
Pea, 99; family, 99, ^xoi ;
fruit of, 7, 165, i68 ; leaves
of^9> 43 ; seed, 2, 7 ; seed,
gemination of, 9, 13
Pear, *04, 106 ; fruit of, 176,
180 #

Pellia, 109, 200
Penicillinm, 207, 208
Perching of pigeon, 271
I’erennial rye grass, 133, 137
Perianth, 119, 121
Pericarp, 167
Petal, 91
Pets, 214
Pigeon, 26s, 270
Pigeons, different breeds of,
279

Pine cones, 160, 162, 171, 174
Pine, Scotch, 160, 161
Pistil, 9T
Plane, 157, 159
Plants and animals, resem-
blances and differences, 243
Plants, respiration of, 243
Play of young animals, 248,
249, 258, 2O2

Plough-share bone of pigeon,
269

Plum, 106; fruit of, 175, 179
j Plumule of bean, 2, 6
Pod, T03

Poison hemlock, 106, 107, 108
Pollen, gt

Pond-life, 340, 357, 378, 379,

Pond-snails, 379, 382
Pouter pigeon, 280
Poplar, 150, 15 X
Poppy, fruit of, 166, i68
Posterior, 217
Potato, 81, 84
Poultry, 296, 299
Precocious birds, 296, 329
Prickles, 75, 77
Piiinrose, ic^S, 109; fertilisa’
tion of, 109

Proboscis of butterfly, 367
Pro-legs of caterpillar, 395
Protective colouration, of
frog, 332 ; of rabbit, 217
Prothallus, of ferns, 184, 185,
188, X91 ; of horsetail, 192,
^95 • »

Pupa, of cabbage - white
butteifly, 363, 366; of

Dytiscus, 361; of tiger-
moth, 364, 369

Rabbit, 21 t ; digestion in, 233
Radicle, of bean, 2, 6 ; of
lupine, 7 ; of pea, 2, 7 ; of
sycamore, 4
Radish, 94, 95
Raspberry, 105, 175, 179
Receptacle, 90

Red, clover, loi, fertilisation
of, loi ; corpuscles of blood,
237, 242

Reproduction, of a grass, 128 ;
of a moss, 201 ; of ferns,
187, i88 ; of flowering plants,
89 : of horsetail, 19s ; of
liverwort, 201 ; of moulds,
208, 209 ; of mushroom, 205
Respiration, 240 ; definition
of, 242 ; of chick-embryo,
294 ; of cockroach, 355 ; of
crustaceans, 376, 377 ; of
fresh-water mussel, 381 ; of
frog, 337 ; of mammals, 24a,
243 ; of pigeon, 279 ; of
snail, 379, 382, 383 ; of tad-
pole, 344

Resting stage, of butter-
fly- 363, 36b ; of Dytiscus,
361

Ribs of rabbit, 217, 223, 277
Rock pigeon, 280
Rodent*;, 220
Rook, 312, 3x8
Root cap, 17

Root, hairs, 17, c8, 30; length-
ening of, x6
Rootlets, 17

Roots, 17, 21, 28; as stoie-
houses of food, 28, 30 ;

432

AN INTROt)UCflON TO NATURE-STUDY*

climbing, 75, 78 ; work of,

" 28* 30

Rdscj jo^, 104; family,, 103;

' fruit 0^, 176, 180 ; leaves pf,

‘ 42

tree, 157
Ruminants, 261
Runner, 80, 82
Rushes, 133, 138
Ryegrass, J33, 137 |

saliva, 233, 234 ^

Sallow willow, 150
Sand-martin, 311, 315
Saugh tree, 150
Scales of Lepidoptera, 364,

367 .

Scotch pine, 160, 161
Secondary thickening, 73
Sedges, 133, 138
Seeds, germination of, 9, 12 ;
of broad bean, i, 5, 9, 13 *,
of maize, 18, 19 ; of mustard,
■ 3 ) 7 * II ; of pea, a, 7 ; of
sycamore, 3, 8, 11, 13 ; of
vegetable marrow, 3, 7, ii ;
of wheat* 18, 19 ; of yellow
lupine, 3, 7, II
Sepal, 90
Sheep, 257, 258
Sheep’s, fescue, 132, 1331 134;

heart, structure of, 235, 237
Shell of hen's egg, 282, 284
Shell, of fresh-water mussel,

378, 381 ; of garden snail,

379, 38a ; of slug, 382
Shepherd’s purse, 93, 95 ; fruit

of, 165
Shoot, 69

Shoulder blade of rabbit, 223,
228

Silicula, 165, 168
Siliqua, 165, 168
Skeleton, leaves, 37, 39 ; of
arthropods, 351 ; of pigeon,
268 ; of rabbit, 217, 222, 226 ;
uses of, 224
Skin of frog, 334, 338
Skull, of pigeon, 268 *, of
rabbit, 217, 222, 226
Skylark, 31 1, 316
Slender foxtail, 134, 135
Smell-sense of moths, 369 ; of
rabbit, 218
Snapdragon, 116
Snowdrop, 120, 122
Soaring, 278
Song-thrush, 301, 303
Sounds of hearjt, 238
Spanish chestnut, 148
Sparrow, 315, 320

Sparrow hawk, 329, 3^^ ^

Spawn, of frog, 339, 34p, 341 J
of Limnaea, 380
SpeedweJ), 115, n6
Spiders, 378
SpikelA, 128, 130,

Spinneret of 363*

365

Spiracles, of cabbage - white
caterpillar, 363, 365 ; of
'cockroach, 350, 355 ,

Spores, of ferns, 184, 185, 187,
190, 191 ; of horsetail, 195 ;
of liverwort, 199, 201 r; of
moss, ijoo, 202 ; of Mucor,
207, 208 ; of mushroom,

, 203, 205 ; of Pcnicfllium, 207,
209

Spruce fir, i6t, 163 ; cones,

^ 171. 174

Squirrels, 178, 220
Stamen, 91
Standard, 100, 102
Starch, 229; action of saliva
on, 230, 23#5 forimtion of,
in leaves, 32, 34 ; m cotyle-
dons, 2, 6 ; in leaves, 48, 50 ;
in twigs. 56 ; test for, 2, 32
Stem, lengthening of, 16
Stems, bleeding of, 67, 70 ;
climbing, 75 ; creeping^ 80,
82 ; duties of, 68 ;• food
chaliiels in, 67, 68, 69, 71 *,
hooking, 75 ; of griLsses, 72,
75 ; of ivy, 75, 77, 78 ;
strengthening of, 71, 72, 75 :
thickening of, 72 ; twining
76, 79 ; underground, 80, 83
Sternum, of pigeon, 269 ; of
rabbit, 217, 223, 227
Stigma, 91
Stipules, 39, 43
Stock, 94

Stolon, 81, 83, 125, 126
Stomach, 231, 232 ; of rumi'
nant, 260
Stomata, 53
Stone fruits, 175, 179
Storm-cock, 302, 307
Strawberry, 105 ; fruit of,
176, t8o, 181
Style of flower, 91
Sugar, 230

Sugar, formation of, in germi
nating pea, 33 ; in grasses,
126

Swallow, 310, 313 ; family,
310, 313

Sweet chestnut, 148
Sweet-scented vernal grass,
„ *37

Swift, 321 322

Iwiipmeiets of crayfish and
lobster, 373,, 375
Sycamore, 157, ,1^ ; buds of,
56, 60; fruit (JT, 3, 8, 171,
173 ; leaves of, 38, 42, 58,
i57» 158' seeds of, 3, 8, ii,

Tadpoles, 941, 344
Tail, of rabbit, 215 ; of tad-
pole, 346, 347

Teeth, of cat, 246, 255 ; of dog,
248, 255 ; of frog, 333, 336 ;
of rabbit, 2#^; of sheep,
257, 259

Tendrils, 43, 76, 79
Tentacles of snail, 379, 382
Thistle, 112, 114
Thorax, of cockroach,, 350,
353 ; of rabbit, 218
Thorns, 75, 78
Throstle, 301, 303
Thrush, 301, 303 ; famfi;^, 301,
303 ; missel, 302, 3*06
Thyme, 118
Tiger-moth, 364, 369
Timoily grass, 132, 135, 13^
'i oadstools, 204, 206
Tongue, of cat, 246, 252 ; ot

„frog, 333.336
Tuber, 81, 84, 191, 194
Tumbler pigeon, 279
Tifrnip, 94, 95
Twining stems, 76, 79, 80

Valves, of heart, 236, 238,
239 ; of veins, 235, 239
Vapourer-moth, 364, 369
Vegetable marrow, seed of,
3, 7, II, 14; fruit of, 176,

179 . «

Vegetable mould, formation
of, by earthworms, 384,
386

Veins, of leaves, 37, 39 ; valves
of, 235, 239
Ventral, 217

Ventricle^of heart, 235, 237
Vertebrae, of pigeon, 269 ; of
rabbit, 223, 227
Vertebral column, 217, 222,
227

^Vertebrates, 220, 35s
Vetch, 100

Violet, fnnt of, 166, 169

Wallflowei?, 88, 89 ; family,
93 , 94 5 fioit of, 165, 167
Warren of rabbit, an, 214

INDEX

433 -

Water, amount of, in plants,
a6; culture, 27; dropfrort,
108 ; hemlock, 108
Wheat seed, i8, 19 ; germina-
tion of, 21

Whiskers, of bat, 2*6 ; of cat,
246, 250 ; of rabbit, 217
White, mould, 207, 20S; of
egg, 283, 28s
Wild oat, 133, 136
Willow, 150 ; fruit of, 171, 173

Windh|v&r, 329, 331
Wind-rown se^, 172
W ing-a)vcrs , of cockroach , 350,
354 ; of beetles, 355, 359, 362
inged seeds, 174
Wings, of bat, 257 ; •f cock-
roach, 3JO, 353 ; of pea
flower, 100, 102 ; of pigeon,
266, 270, 273

Wood 70, 71, 72 ; avens, fruit
of, 174, 177 ; louse, 377 *

Wool, 257. 258
“Woolly bear," 364, 369
Worm castings, 384, 386
WoiTOs, 383

Yei.lowoat grass, 137
Yolk of hen s egg, 283, 285
Yorkshire fog, 125, 139^

GLASGOW : PRINTED AT THE UNIVERSITY PRESS BY ROBERT MACLEHOSE AND CO. LTD.

A HEALTH OlEADER

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